U.S. patent application number 09/819376 was filed with the patent office on 2001-11-08 for methods for treating ovarian cancer, poly (phosphoester) compositions, and biodegradable articles for same.
Invention is credited to Dang, Wenbin.
Application Number | 20010038849 09/819376 |
Document ID | / |
Family ID | 22854735 |
Filed Date | 2001-11-08 |
United States Patent
Application |
20010038849 |
Kind Code |
A1 |
Dang, Wenbin |
November 8, 2001 |
Methods for treating ovarian cancer, poly (phosphoester)
compositions, and biodegradable articles for same
Abstract
A biodegradable polymer compositions suitable for
intraperitoneal administration to treat a mammalian subject having
ovarian cancer are described, the composition comprising: (a) at
least one antineoplastic agent and (b) a biodegradable polymer
comprising the recurring monomeric units shown in formula I: 1
wherein X is --O-- or --NR.sup.4--, where R.sup.4 is H or alkyl; Y
is --O--, --S-- or --NR.sup.4--; each of R.sup.1 and R.sup.2 is a
divalent organic moiety; L is a divalent, branched or straight
chain aliphatic group having 1-20 carbon atom, a cycloaliphatic
group, or a group having the formula: 2 R.sup.3 is selected from
the group consisting of H, alkyl, alkoxy, aryl, aryloxy,
heterocyclic or heterocycloxy; and n is about 5-5,000; wherein the
polymer composition provides extended release of the antineoplastic
agent into the peritoneum of the subject; wherein the polymer
composition increases the median survival rate from the cancer by
at least about 10%, as compared with the median survival rate
obtained by administration of a composition comprising the same
dosage of the antineoplastic agent without the biodegradable
polymer. Solid articles and methods for treating ovarian cancer are
also described.
Inventors: |
Dang, Wenbin; (Ellicott
City, MD) |
Correspondence
Address: |
FOLEY, HOAG & ELIOT, LLP
PATENT GROUP
ONE POST OFFICE SQUARE
BOSTON
MA
02109
US
|
Family ID: |
22854735 |
Appl. No.: |
09/819376 |
Filed: |
March 28, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09819376 |
Mar 28, 2001 |
|
|
|
09227852 |
Jan 11, 1999 |
|
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Current U.S.
Class: |
424/428 ;
424/486 |
Current CPC
Class: |
A61P 35/00 20180101;
A61K 9/1647 20130101; Y10S 977/911 20130101; A61K 9/7007 20130101;
Y10S 977/912 20130101 |
Class at
Publication: |
424/428 ;
424/486 |
International
Class: |
A61K 009/42; A61K
009/14 |
Claims
We claim:
1. A biodegradable polymer composition suitable for intraperitoneal
administration to treat a mammalian subject having ovarian cancer,
said composition comprising: (a) at least one antineoplastic agent
and (b) a biodegradable polymer comprising the recurring monomeric
units shown in formula I: 36wherein X is --O-- or --NR.sup.4--,
where R.sup.4 is H or alkyl; Y is --O--, --S-- or --NR.sup.4--;
each of R.sup.1 and R.sup.2 is a divalent organic moiety; L is a
divalent, branched or straight chain aliphatic group having 1-20
carbon atom, a cycloaliphatic group, or a group having the formula:
37R.sup.3 is selected from the group consisting of H, alkyl,
alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; and n is
about 5-5,000; wherein said polymer composition provides extended
release of said antineoplastic agent into the peritoneum of said
subject; wherein said polymer composition increases the median
survival rate from said cancer by at least about 10%, as compared
with the median survival rate obtained by administration of a
composition comprising the same dosage of said antineoplastic agent
without said biodegradable polymer.
2. The composition of claim 1 wherein said polymer composition
increases the median survival rate from said cancer by at least
about 20%, as compared with the median survival rate obtained by
administration of a composition comprising the same dosage of said
antineoplastic agent without said biodegradable polymer.
3. The polymer composition of claim 1 wherein said composition
increases the median survival rate from said cancer by at least
about 30%, as compared with the median survival rate obtained by
administration of a composition comprising the same dosage of said
antineoplastic agent without said biodegradable polymer.
4. The polymer composition of claim 1 wherein a single dose of said
polymer composition provides extended release of said
antineoplastic agent over a time of at least 28 days.
5. The polymer composition of claim 1 wherein said polymer is
selected from the group consisting of: 38wherein: M.sup.1 and
M.sup.2 are each independently (1) a branched or straight chain
aliphatic group having from 1-20 carbon atoms; or (2) a branched or
straight chain, oxy-, carboxy- or amino-aliphatic group having from
1-20 carbon atoms; the molar ratio of x:y is about 1; the molar
ratio n:(x or y) is between about 200:1 and 1:200; and the molar
ratio q:r is between about 1:99 and 99:1.
6. A biodegradable polymer composition suitable for intraperitoneal
administration to treat a mammalian subject having ovarian cancer,
said composition comprising: (a) at least one antineoplastic agent
and (b) a biodegradable polymer comprising the recurring monomeric
units shown in formula II: 39wherein each of R.sup.1 and R.sup.2 is
a divalent organic moiety; R.sup.3 is selected from the group
consisting of alkoxy, aryloxy and heterocycloxy; x is .gtoreq.1; y
is 2; and n is about 5-5,000; wherein said polymer composition
provides extended release of said antineoplastic agent into the
peritoneum of said subject; wherein said composition increases the
median survival rate from said cancer by at least about 10%, as
compared with the median survival rate obtained by administration
of a composition comprising the same dosage of said antineoplastic
agent without said biodegradable polymer.
7. The polymer composition of claim 6 wherein a single dose of said
polymer composition provides extended release of said
antineoplastic agent over a time of at least 28 days.
8. The composition of claim 6 wherein R.sup.1 and R.sup.2 are each
independently an alkylene group, a cycloaliphatic group, a
phenylene group, or a divalent group having the formula: 40wherein
Z is oxygen, nitrogen, or sulfur, and m is 1 to 3.
9. The composition of claim 6 wherein R.sup.1 and R.sup.2 are each
independently an alkylene group having from 1 to 7 carbons
atoms.
10. The composition of claim 6 wherein R.sup.1 and R.sup.2 are each
an ethylene group.
11. The composition of claim 6 wherein R.sup.1 and R.sup.2 are each
an n-propylene group.
12. The composition of claim 6 wherein R.sup.1 and R.sup.2 are each
a 2-methyl-propylene group.
13. The composition of claim 6 wherein R.sup.1 and R.sup.2 are each
a 2,2'-dimethyl-propylene group.
14. The composition of claim 6 wherein R.sup.3 is an alkoxy group
or a phenoxy group.
15. The composition of claim 6 wherein R.sup.3 is an alkoxy group
having from 1 to 7 carbon atoms.
16. The composition of claim 6 wherein R.sup.3 is an ethoxy
group.
17. The composition of claim 6 wherein x is from about 0.1 to about
30, and y is 2.
18. The composition of claim 6 wherein x is from about 0.2 to about
20, and y is 2.
19. The composition of claim 6 wherein x is from about 2 to about
20, and y is 2.
20. A biodegradable polymer composition suitable for
intraperitoneal administration to treat a mammalian subject having
ovarian cancer, said composition comprising: (a) at least one
antineoplastic agent and (b) a biodegradable polymer comprising the
recurring monomeric units shown in formula III or IV: 41wherein X
is --O-- or --NR.sup.4-- where R.sup.4 is H or alkyl; Y is --O--,
--S-- or --NR.sup.4--; M.sup.1 and M.sup.2 are each independently
(1) a branched or straight chain aliphatic group having from 1-20
carbon atoms; or (2) a branched or straight chain, oxy-, carboxy-
or amino-aliphatic group having from 1-20 carbon atoms; L is a
divalent, branched or straight chain aliphatic group having 1-20
carbon atom; R.sup.3 is selected from the group consisting of H,
alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; the
molar ratio of x:y is about 1; the molar ratio n:(x or y) is
between about 200:1 and 1:200; the molar ratio q:r is between about
1:99 and 99:1; and n is about 5-5,000; wherein said polymer
composition provides extended release of said antineoplastic agent
into the peritoneum of said subject; wherein said composition
increases the median survival rate from said cancer by at least
about 10%, as compared with the median survival rate obtained by
administration of a composition comprising the same dosage of said
antineoplastic agent without said biodegradable polymer.
21. The polymer composition of claim 20 wherein a single dose of
said polymer composition provides extended release of said
antineoplastic agent over a time of at least 28 days.
22. The composition of claim 20 wherein each of M' and L is a
branched or straight chain alkylene group.
23. The composition of claim 20 wherein each of MI and L has from 1
to 7 carbon atoms.
24. The composition of claim 20 wherein M.sup.1 is an ethylene
group or a methyl-substituted methylene group, and L is an ethylene
group.
25. The composition of claim 20 wherein R.sup.3 is an alkyl group,
an alkoxy group, a phenyl group, a phenoxy group, or a
heterocycloxy group.
26. The composition of claim 20 wherein R.sup.3 is an alkoxy group
having from 1 to 7 carbon atoms.
27. The composition of claim 20 wherein R.sup.3 is an ethoxy
group.
28. The composition of claim 20 wherein each of M.sup.1 and M.sup.2
is a branched or straight chain alkylene group.
29. The composition of claim 20 wherein-at least one of M.sup.1 and
M.sup.2 is an alkylene or alkoxylene group having a formula
selected from the group consisting of --(CH.sub.2).sub.a--,
--(CH.sub.2).sub.a--O--, and
--(CH.sub.2).sub.a--O--(CH.sub.2).sub.b--, wherein each of a and b
is 1-7.
30. The composition of claim 20 wherein at least one of M.sup.1 and
M.sup.2 has the formula: --CHR'--CO--O--CHR"--, wherein R' and R"
are each independently H, alkyl, alkoxy, aryl, aryloxy,
heterocyclic or heterocycloxy.
31. The composition of claim 20 wherein each of M.sup.1 and M.sup.2
has from 1 to 7 carbon atoms.
32. The composition of claim 20 wherein X is --O--.
33. The composition of claim 20 wherein X is --NR.sup.4--.
34. The composition of claim 20 wherein: M.sup.1 and M.sup.2 are
each an alkylene or alkoxylene group; L is an alkylene group; X is
--O--; and R.sup.3 is an alkoxy group.
35. The composition of claim 20 wherein the molar ratio x:y is
about 1.
36. The composition of claim 20 wherein the molar ratio q:r is
about 1:99 and 99:1.
37. The composition of claim 20 wherein each of x and y is about 1
to 1,000.
38. The composition of claim 20 wherein the molar ratio n:(x or y)
is between about 100:1 and 1:100.
39. A biodegradable polymer composition suitable for
intraperitoneal administration to treat a mammalian subject having
ovarian cancer, said composition comprising: (a) at least one
antineoplastic agent and (b) a biodegradable polymer comprising the
recurring monomeric units shown in formula V: 42wherein each of
R.sup.1 and R.sup.2 is independently straight or branched
aliphatic, either unsubstituted or substituted with one or more
non-interfering substituents; and L is a divalent cycloaliphatic
group; R.sup.3 is selected from the group consisting of H, alkyl,
alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; and n is
about 5-5,000; wherein said polymer composition provides extended
release of said antineoplastic agent into the peritoneum of said
subject; wherein said composition increases the median survival
rate from said cancer by at least about 10%, as compared with the
median survival rate obtained by administration of a composition
comprising the same dosage of said antineoplastic agent without
said biodegradable polymer.
40. The polymer composition of claim 39 wherein a single dose of
said polymer composition provides extended release of said
antineoplastic agent over a time of at least 28 days.
41. The composition of claim 39 wherein each of R.sup.1 and R.sup.2
is a branched or straight chain alkylene group having from one to
seven carbon atoms.
42. The composition of claim 39 wherein each of R.sup.1 and R.sup.2
is a methylene group or an ethylene group.
43. The composition of claim 39 wherein R.sup.3 is an alkoxy
group.
44. The composition of claim 39 wherein R.sup.3 is hexyloxy.
45. The composition of claim 39 wherein n is 5 to 500.
46. The composition of claim 39 wherein L is a cycloaliphatic
group, either unsubstituted or substituted with a non-interfering
substituent.
47. The composition of claim 39 wherein L is cyclohexylene.
48. The composition of claim 1 wherein said polymer is prepared by
solution polymerization.
49. The composition of claim 1 wherein said polymer is prepared by
melt polymerization.
50. The composition of claim 1 wherein said polymer comprises
additional biocompatible monomeric units or is blended with other
biocompatible polymers.
51. The composition of claim 1 wherein said polymer is soluble in
at least one of the solvents selected from the group consisting of
acetone, dimethylene chloride, chloroform, ethyl acetate, DMAC,
N-methyl pyrrolidone, dimethylformamide and dimethylsulfoxide.
52. The composition of claim 1 wherein said antineoplastic agent
comprises paclitaxel.
53. The composition of claim 1 wherein the molecular weight (Mw) of
said polymer is from about 2,000 to 400,000 daltons.
54. The composition of claim 1 wherein said antineoplastic agent
and said polymer form an amorphous, monolithic matrix.
55. The composition of claim 1 in the form of microparticles, a
flexible film, a viscous liquid, wafers or rods.
56. The composition of claim 1 in the form of spray-dried
microspheres.
57. The composition of claim 1 wherein the composition comprises
about 5-15% by weight of the antineoplastic agent.
58. A biodegradable polymer composition suitable for
intraperitoneal administration to treat a mammalian subject having
ovarian cancer, said composition comprising: (a) paclitaxel and (b)
a biodegradable polymer comprising the recurring monomeric units
shown in formula VI: 43wherein the molar ratio of x:y is about 1;
the molar ratio n:(x or y) is between about 200:1 and 1:200; and n
is about 5-5,000; wherein said polymer composition provides
extended release of said antineoplastic agent into the
peritoneum-of said subject; wherein said polymer composition
increases the median survival rate from said cancer by at least
about 10%, as compared with the median survival rate obtained by
administration of a composition comprising the same dosage of said
antineoplastic agent without said biodegradable polymer.
59. A solid article suitable for insertion into the peritoneum to
treat a mammalian subject having ovarian cancer, said article
comprising a biodegradable polymer composition comprising: (a) at
least one antineoplastic agent and (b) a biodegradable polymer
comprising the recurring monomeric units shown in formula I:
44wherein X is --O-- or --NR.sup.4--, where R.sup.4 is H or alkyl;
Y is --O--, --S--or --NR.sup.4--; each of R.sup.1 and R.sup.2 is a
divalent organic moiety; L is a divalent, branched or straight
chain aliphatic group having 1-20 carbon atom, a cycloaliphatic
group, or a group having the formula: 45R.sup.3 is selected from
the group consisting of H, alkyl, alkoxy, aryl, aryloxy,
heterocyclic or heterocycloxy; and n is about 5-5,000; wherein said
polymer composition provides extended release of said
antineoplastic agent into the peritoneum of said subject; wherein
said composition increases the median survival rate from said
cancer by at least about 10%, as compared with the median survival
rate obtained by administration of a composition comprising the
same dosage of said antineoplastic agent without said biodegradable
polymer.
60. The article of claim 59 wherein a single dose of said polymer
composition provides extended release of said antineoplastic agent
over a time of at least 28 days.
61. The article of claim 59 wherein said composition increases the
median survival rate from said cancer by at least about 20%, as
compared with the median survival rate obtained by administration
of a composition comprising the same dosage of said antineoplastic
agent without said biodegradable polymer.
62. The article of claim 59 wherein said composition increases the
median survival rate from said cancer by at least about 30%, as
compared with the median survival rate obtained by administration
of a composition comprising the same dosage of said antineoplastic
agent without said biodegradable polymer.
63. The article of claim 59 wherein said polymer is selected from
the group consisting of: wherein: 46wherein M.sup.1 and M.sup.2 are
each independently (1) a branched or straight chain aliphatic group
having from 1-20 carbon atoms; or (2) a branched or straight chain,
oxy-, carboxy- or amino-aliphatic group having from 1-20 carbon
atoms; the molar ratio of x:y is about 1; the molar ratio n:(x or
y) is between about 200:1 and 1:200; and the molar ratio q:r is
between about 1:99 and 99:1.
64. A solid article suitable for insertion into the peritoneum to
treat a mammalian subject having ovarian cancer, said article
comprising a biodegradable polymer composition comprising: (a) at
least one antineoplastic agent and (b) a biodegradable polymer
comprising-the recurring monomeric units shown in formula II:
47wherein each of R.sup.1 and R.sup.1 is a divalent organic is
moiety; R.sup.1 is selected from the group consisting of alkoxy,
aryloxy and heterocycloxy; x is .gtoreq.1; y is 2; and n is about
5-5,000; wherein said polymer composition provides extended release
of said antineoplastic agent into the peritoneum of said subject;
wherein said composition increases the median survival rate from
said cancer by at least about 10%, as compared with the median
survival rate obtained by administration of a composition
comprising the same dosage of said antineoplastic agent without
said biodegradable polymer.
65. The article of claim 64 wherein a single dose of said polymer
composition provides extended release of said antineoplastic agent
over a time of at least 28 days.
66. The article of claim 64 wherein R.sup.1 and R.sup.2 are each
independently an alkylene group, a cycloaliphatic group, a
phenylene group, or a divalent group having the formula: 48wherein
Z is oxygen, nitrogen, or sulfur, and m is 1 to 3.
67. The article of claim 64 wherein R.sup.1 and R.sup.2 are each
independently an alkylene group having from 1 to 7 carbons
atoms.
68. The article of claim 64 wherein R.sup.1 and R.sup.2 are each an
ethylene group.
69. The article of claim 64 wherein R.sup.1 and R.sup.2 are each an
n-propylene group.
70. The article of claim 64 wherein R.sup.1 and R.sup.2 are each a
2-methyl-propylene group.
71. The article of claim 64 wherein R.sup.1 and R.sup.2 are each a
2,2'-dimethyl-propylene group.
72. The article of claim 64 wherein R.sup.3 is an alkoxy group or a
phenoxy group.
73. The article of claim 64 wherein R.sup.3 is an alkoxy group
having from 1 to 7 carbon atoms.
74. The article of claim 64 wherein R.sup.3 is an ethoxy group.
75. The article of claim G4 wherein x is from about 0.1 to about
30, and y is 2.
76. The article of claim 64 wherein x is from about 0.2 to about
20, and y is 2.
77. The article of claim 64 wherein x is from about 2 to about 20,
and y is 2.
78. A solid article suitable for insertion into the peritoneum to
treat a mammalian subject having ovarian cancer, said article
comprising a biodegradable polymer composition suitable for
intraperitoneal administration to treat a mammalian subject having
ovarian cancer, said composition comprising: (a) at least one
antineoplastic agent and (b) a biodegradable polymer comprising the
recurring monomeric units shown in formula III or IV: 49wherein X
is --O-- or --NR.sup.4--, where R.sup.4 is H or alkyl; Y is --O--,
--S-- or --NR.sup.4--; M.sup.1 and M.sup.2 are each independently
(1) a branched or straight chain aliphatic group having from 1-20
carbon atoms; or (2) a branched or straight chain, oxy-, carboxy-
or amino-aliphatic group having from 1-20 carbon atoms; L is a
divalent, branched or straight chain aliphatic group having 1-20
carbon atom; R.sup.3 is selected from the group consisting of H,
alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; the
molar ratio of x:y is about 1; the molar ratio n:(x or y) is
between about 200:1 and 1:200; the molar ratio q:r is between about
1:99 and 99:1; and n is about 5-5,000; wherein said polymer
composition provides extended release of said antineoplastic agent
into the peritoneum of said subject; wherein said composition
increases the median survival rate from said cancer by at least
about 10%, as compared with the median survival rate obtained by
administration of a composition comprising the same dosage of said
antineoplastic agent without said biodegradable polymer.
79. The article of claim 78 wherein a single dose of said polymer
composition provides extended release of said antineoplastic agent
over a time of at least 28 days.
80. The article of claim 78 wherein each of M.sup.1 and L is a
branched or straight chain alkylene group.
81. The article of claim 78 wherein each of M.sup.1 and L has from
1 to 7 carbon atoms.
82. The article of claim 78 wherein M.sup.1 is an ethylene group or
a methyl-substituted methylene group, and L is an ethylene
group.
83. The article of claim 78 wherein R.sup.3 is an alkyl group, an
alkoxy group, a phenyl group, a phenoxy group, or a heterocycloxy
group.
84. The article of claim 78 wherein R.sup.3 is an alkoxy group
having from 1 to 7 carbon atoms.
85. The article of claim 78 wherein R.sup.3 is an ethoxy group.
86. The article of claim 78 wherein each of M.sup.1 and M.sup.2 is
a branched or straight chain alkylene group.
87. The article of claim 78 wherein at least one of M.sup.1 and
M.sup.2 is an alkylene or alkoxylene group having a formula
selected from the group consisting of
--(CH.sub.2).sub.a--(CH.sub.2).sub.a--O--, and
--(CH.sub.2).sub.a--O--(CH.sub.2).sub.b--, wherein each of a and b
is 1-7.
88. The article of claim 78 wherein at least one of M.sup.1 and
M.sup.2 has the formula: --CHR'--CO--O--CHR"--, wherein R' and R"
are each independently H, alkyl, alkoxy, aryl, aryloxy,
heterocyclic or heterocycloxy.
89. The article of claim 78 wherein each of M.sup.1 and M.sup.2 has
from 1 to 7 carbon atoms.
90. The article of claim 78 wherein X is --O--.
91. The article of claim 78 wherein X is --NR.sup.4--.
92. The article of claim 78 wherein: M.sup.1 and M.sup.2 are each
an alkylene or alkoxylene group; L is an alkylene group; X is
--O--; and R.sup.3 is an alkoxy group.
93. The article of claim 78 wherein the molar ratio x:y is about
1.
94. The article of claim 78 wherein the molar ratio q:r is about
1:99 and 99:1.
95. The article of claim 78 wherein each of x and y is about 1 to
1,000.
96. The article of claim 78 wherein the molar ratio n:(x or y) is
between about 100:1 and 1:100.
97. A solid article suitable for insertion into the peritoneum to
treat a mammalian subject having ovarian cancer, said article
comprising a biodegradable polymer composition suitable for
intraperitoneal administration to treat a mammalian subject having
ovarian cancer, said composition comprising: (a) at least one
antineoplastic agent and (b) a biodegradable polymer comprising the
recurring monomeric units shown in formula V: 50wherein each of
R.sup.1 and R.sup.2 is independently straight or branched
aliphatic, either unsubstituted or substituted with one or more
non-interfering substituents; and L is a divalent cycloaliphatic
group; R.sup.3 is selected from the group consisting of H, alkyl,
alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; and n is
about 5-5,000; wherein said polymer composition provides extended
release of said antineoplastic agent into the peritoneum of said
subject; wherein said composition increases the median survival
rate from said cancer by at least about 10%, as compared with the
median survival rate obtained by administration of a composition
comprising the same dosage of said antineoplastic agent without
said biodegradable polymer.
98. The article of claim 97 wherein a single dose of said polymer
composition provides extended release of said antineoplastic agent
over a time of at least 28 days.
99. The article of claim 97 wherein each of R.sup.1 and R.sup.2 is
a branched or straight chain alkylene group having from one to
seven carbon atoms.
100. The article of claim 97 wherein each of R.sup.1 and R.sup.2 is
a methylene group or an ethylene group.
101. The article of claim 97 wherein R.sup.3 is an alkoxy
group.
102. The article of claim 97 wherein R.sup.3 is hexyloxy.
103. The article of claim 97 wherein n is 5 to 500.
104. The article of claim 97 wherein L is a cycloaliphatic group,
either unsubstituted or substituted with a non-interfering
substituent.
105. The article of claim 97 wherein L is cyclohexylene.
106. The article of claim 97 wherein said polymer is prepared by
solution polymerization.
107. The article of claim 59 wherein said polymer is prepared by
melt polymerization.
108. The article of claim 59 wherein said polymer comprises
additional biocompatible monomeric units or is blended with other
biocompatible polymers.
109. The article of claim 59 wherein said polymer is soluble in at
least one of the solvents selected from the group consisting of
acetone, dimethylene chloride, chloroform, ethyl acetate, DMAC,
N-methyl pyrrolidone, dimethylformamide and dimethylsulfoxide.
110. The article of claim 59 wherein said antineoplastic agent
comprises paclitaxel.
111. The article of claim 59 wherein the molecular weight (Mw) of
said polymer is from about 2,000 to 400,000 daltons.
112. The article of claim 59 wherein said antineoplastic agent and
said polymer form an amorphous, monolithic matrix.
113. The article of claim 59 wherein said antineoplastic agent is
encapsulated within said polymer.
114. The article of claim 59 wherein said article results in
minimal irritation to non-neoplastic tissues when implanted or
injected into vasculated tissue.
115. The article of claim 59 wherein said article is in the form of
a flexible film, a wafer or a rod.
116. The article of claim 59 wherein said article is in the form of
one or more injectable microparticles.
117. The article of claim 59 in the form of spray-dried
microspheres.
118. The article of claim 59 wherein the composition comprises
about 5-15% by weight of the antineoplastic agent.
119. A solid article suitable for insertion into the peritoneum to
treat a mammalian subject having ovarian cancer, said article
comprising a biodegradable polymer composition suitable for
intraperitoneal administration to treat a mammalian subject having
ovarian cancer, said composition comprising: (a) paclitaxel and (b)
a biodegradable polymer comprising the recurring monomeric units
shown in formula VI: 51wherein the molar ratio of x:y is about 1;
the molar ratio n:(x or y) is between about 200:1 and 1:200; and n
is about 5-5,000; wherein said polymer composition provides
extended release of said antineoplastic agent into the peritoneum
of said subject; wherein said composition increases the median
survival rate from said cancer by at least about 10%, as compared
with the median survival rate obtained by administration of a
composition comprising the same dosage of said antineoplastic agent
without said biodegradable polymer.
120. A method for treating a mammalian subject having ovarian
cancer, by the extended release of an antineoplastic agent, said
method comprising the steps of: (a) combining the antineoplastic
agent with a biodegradable polymer having the recurring monomeric
units shown in formula I: 52wherein X is --O-- or --NR.sup.4--,
where R.sup.4 is H or alkyl; Y is --O--, --S-- or --NR.sup.4--;
each of R.sup.1 and R.sup.2 is a divalent organic moiety; L is a
divalent, branched or straight chain aliphatic group having 1-20
carbon atom, a cycloaliphatic group, or a group having the formula:
53R.sup.3 is selected from the group consisting of H, alkyl,
alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; and n is
5-5,000; to form a composition; and (b) inserting said composition
in vivo into the peritoneum of said subject, such that the inserted
composition is in at least partial contact with an ovarian cancer
tumor, wherein the median survival rate from said cancer is
increased by at least about 10%, as compared with the median
survival rate obtained by administration of a composition
comprising the same dosage of said antineoplastic agent without
said biodegradable polymer.
121. The method of claim 120 wherein a single dose of said polymer
composition provides extended release of said antineoplastic agent
over a time of at least 28 days.
122. The method of claim 120 wherein said composition increases the
median survival rate from said cancer by at least about 20%, as
compared with the median survival rate obtained by administration
of a composition comprising the same dosage of said antineoplastic
agent without said biodegradable polymer.
123. The method of claim 120 wherein said composition increases the
median survival rate from said cancer by at least about 30%, as
compared with the median survival rate obtained by administration
of a composition comprising the same dosage of said antineoplastic
agent without said biodegradable polymer.
124. The method of claim 120 wherein said polymer is selected from
the group consisting of: 54wherein: M.sup.1 and M.sup.2 are each
independently (1) a branched or straight chain aliphatic group
having from 1-20 carbon atoms; or (2) a branched or straight chain,
oxy-, carboxy- or amino-aliphatic group having from 1-20 carbon
atoms; the molar ratio of x:y is about 1; the molar ratio n:(x or
y) is between about 200:1 and 1:200; and the molar ratio q:r is
between about 1:99 and 99:1.
125. A method for treating a mammalian subject having ovarian
cancer, by the extended release of an antineoplastic agent, said
method comprising the steps of: (a) combining the antineoplastic
agent with a biodegradable polymer having the recurring monomeric
units shown in formula II: 55wherein each of R.sup.1 and R.sup.2 is
a divalent organic moiety; R.sup.3 is selected from the group
consisting of alkoxy, aryloxy and heterocycloxy; x is .gtoreq.1; y
is 2; and n is about 5-5,000; and (b) inserting said composition in
vivo into the peritoneum of said subject, such that the inserted
composition is in at least partial contact with an ovarian cancer
tumor, wherein the median survival rate from said cancer is
increased by at least about 10%, as compared with the median
survival rate obtained by administration of a composition
comprising the same dosage of said antineoplastic agent without
said biodegradable polymer.
126. The method of claim 125 wherein a single dose of said polymer
composition provides extended release of said antineoplastic agent
over a time of at least 28 days.
127. The method of claim 125 wherein R.sup.1 and R.sup.2 are each
independently an alkylene group, a cycloaliphatic group, a
phenylene group, or a divalent group having the formula: 56wherein
Z is oxygen, nitrogen, or sulfur, and m is 1 to 3.
128. The method of claim 125 wherein R.sup.1 and R.sup.2 are each
independently an alkylene group having from 1 to 7 carbons
atoms.
129. The method of claim 125 wherein R.sup.1 and R.sup.2 are each
an ethylene group.
130. The method of claim 125 wherein R.sup.1 and R.sup.2 are each
an n-propylene group.
131. The method of claim 125 wherein R.sup.1 and R.sup.2 are each a
2-methyl-propylene group.
132. The method of claim 125 wherein R.sup.1 and R.sup.2 are each a
2,2'-dimethyl-propylene group.
133. The method of claim 125 wherein R.sup.3 is an alkoxy group or
a phenoxy group.
134. The method of claim 125 wherein R.sup.3 is an alkoxy group
having from 1 to 7 carbon atoms.
135. The method of claim 125 wherein R.sup.3 is an ethoxy
group.
136. The method of claim 125 wherein x is from about 0.1 to about
30, and y is 2.
137. The method of claim 125 wherein x is from about 0.2 to about
20, and y is 2.
138. The method of claim 125 wherein x is from about 2 to about 20,
and y is 2.
139. A method for treating a mammalian subject having ovarian
cancer, by the extended release of an antineoplastic agent, said
method comprising the steps of: (a) combining the antineoplastic
agent with a biodegradable polymer having the recurring monomeric
units shown in formula III or IV: 57wherein X is --O-- or
--NR.sup.4--, where R.sup.4 is H or alkyl; Y is --O--, --S-- or
--NR.sup.4--; M.sup.1 and M.sup.2 are each independently (1) a
branched or straight chain aliphatic group having from 1-20 carbon
atoms; or (2) a branched or straight chain, oxy-, carboxy- or
amino-aliphatic group having from 1-20 carbon atoms; L is a
divalent, branched or straight chain aliphatic group having 1-20
carbon atom; R.sup.3 is selected from the group consisting of H,
alkyl, alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; the
molar ratio of x:y is about 1; the molar ratio n:(x or y) is
between about 200:1 and 1:200; the molar ratio q:r is between about
1:99 and 99:1; and n is about 5-5,000; and (b) inserting said
composition in vivo into the peritoneum of said subject, such that
the inserted composition is in at least partial contact with an
ovarian cancer tumor, wherein the median survival rate from said
cancer is increased by at least about 10%, as compared with the
median survival rate obtained by administration of a composition
comprising the same dosage of said antineoplastic agent without
said biodegradable polymer.
140. The method of claim 139 wherein a single dose of said polymer
composition provides extended release of said antineoplastic agent
over a time of at least 28 days.
141. The method of claim 139 wherein each of Ml and L is a branched
or straight chain alkylene group.
142. The method of claim 139 wherein each of M.sup.1 and L has from
1 to 7 carbon atoms.
143. The method of claim 139 wherein M.sup.1 is an ethylene group
or a methyl-substituted methylene group, and L is an ethylene
group.
144. The method of claim 139 wherein R.sup.3 is an alkyl group, an
alkoxy group, a phenyl group, a phenoxy group, or a heterocycloxy
group.
145. The method of claim 139 wherein R.sup.3 is an alkoxy group
having from 1 to 7 carbon atoms.
146. The method of claim 139 wherein R.sup.3 is an ethoxy
group.
147. The method of claim 139 wherein each of M.sup.1 and M.sup.2 is
a branched or straight chain alkylene group.
148. The method of claim 139 wherein at least one of M.sup.1 and
M.sup.2 is an alkylene or alkoxylene group having a formula
selected from the group consisting of
--(CH.sub.2).sub.a--(CH.sub.2).sub.a--O--, and
--(CH.sub.2).sub.a--O--(CH.sub.2).sub.b--, wherein each of a and b
is 1-7.
149. The method of claim 139 wherein at least one of M.sup.1 and
M.sup.2 has the formula: --CHR'--CO--O--CHR"--, wherein R' and R"
are each independently H, alkyl, alkoxy, aryl, aryloxy,
heterocyclic or heterocycloxy.
150. The method of claim 139 wherein each of M.sup.1 and M.sup.2
has from 1 to 7 carbon atoms.
151. The method of claim 139 wherein X is --O--.
152. The method of claim 139 wherein X is --NR.sup.4--.
153. The method of claim 139 wherein: M.sup.1 and M.sup.2 are each
an alkylene or alkoxylene group; L is an alkylene group; X is
--O--; and R.sup.3 is an alkoxy group.
154. The method of claim 139 wherein the molar ratio x:y is about
1.
155. The method of claim 139 wherein the molar ratio q:r is about
1:99 and 99:1.
156. The method of claim 139 wherein each of x and y is about 1 to
1,000.
157. The method of claim 139 wherein the molar ratio n:(x or y) is
between about 100:1 and 1:100.
158. A method for treating a mammalian subject having ovarian
cancer, by the extended release of an antineoplastic agent, said
method comprising the steps of: (a) combining the antineoplastic
agent with a biodegradable polymer having the monomeric units shown
in formula V: 58wherein each of R.sup.1 and R.sup.2 is
independently straight or branched aliphatic, either unsubstituted
or substituted with one or more non-interfering substituents; and L
is a divalent cycloaliphatic group; R.sup.3 is selected from the
group consisting of H, alkyl, alkoxy, aryl, aryloxy, heterocyclic
or heterocycloxy; and n is about 5-5,000; and (b) inserting said
composition in viva into the peritoneum of said subject, such that
the inserted composition is in at least partial contact with an
ovarian cancer tumor, wherein the median survival rate from said
cancer is increased by at least about 10%, as compared with the
median survival rate obtained by administration of a composition
comprising the same dosage of said antineoplastic agent without
said biodegradable polymer.
159. The method of claim 158 wherein a single dose of said polymer
composition provides extended release of said antineoplastic agent
over a time of at least 28 days.
160. The method of claim 158 wherein each of R.sup.1 and R.sup.2is
a branched or straight chain alkylene group having from one to
seven carbon atoms.
161. The method of claim 158 wherein each of R.sup.1 and R.sup.2 is
a methylene group or an ethylene group.
162. The method of claim 158 wherein R.sup.1 is an alkoxy
group.
163. The method of claim 158 wherein R.sup.3 is hexyloxy.
164. The method of claim 158 wherein n is 5 to 500.
165. The method of claim 158 wherein L is a cycloaliphatic group,
either unsubstituted or substituted with a non-interfering
substituent.
166. The method of claim 158 wherein L is cyclohexylene.
167. The method of claim 120 wherein said polymer is prepared by
solution polymerization.
168. The method of claim 120 wherein said polymer is prepared by
melt polymerization.
169. The method of claim 120 wherein said polymer comprises
additional biocompatible monomeric units or is blended with other
biocompatible polymers.
170. The method of claim 120 wherein said polymer is soluble in at
least one of the solvents selected from the group consisting of
acetone, dimethylene chloride, chloroform, ethyl acetate, DMAC,
N-methyl pyrrolidone, dimethylformamide and dimethylsulfoxide.
171. The method of claim 120 wherein said antineoplastic agent
comprises paclitaxel.
172. The method of claim 120 wherein the molecular weight (Mw) of
said polymer is from about 2,000 to 400,000 daltons.
173. The method of claim 120 wherein said antineoplastic agent and
said polymer form an amorphous, monolithic matrix.
174. The method of claim 120 wherein said antineoplastic agent is
encapsulated within said polymer.
175. The method of claim 120 wherein said article results in
minimal irritation to non-neoplastic tissues when implanted or
injected into vasculated tissue.
176. The method of claim 120 wherein said composition is a viscous
liquid.
177. The method of claim 120 wherein said composition is formed
into a shaped, solid article.
178. The method of claim 120 wherein said article is in the form of
a flexible film, a wafer or a rod.
179. The method of claim 120 wherein said article is in the form of
one or more injectable microparticles.
180. The method of claim 120 wherein the composition comprises
about 5-15% by weight of the antineoplastic agent.
181. A method for treating a mammalian subject having ovarian
cancer, by the extended release of paclitaxel, said method
comprising the steps of: (a) combining the paclitaxel with a
biodegradable polymer having the recurring monomeric units shown in
formula VI: 59wherein the molar ratio of x:y is about 1; the molar
ratio n:(x or y) is between about 200:1 and 1:200; and n is about
5-5,000; to form a composition; and (b) inserting said composition
in vivo into the peritoneum of said subject, such that the inserted
composition is in at least partial contact with an ovarian cancer
tumor, wherein the median survival rate from said cancer is
increased by at least about 10%, as compared with the median
survival rate obtained by administration of a composition
comprising the same dosage of said antineoplastic agent without
said biodegradable polymer.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to methods for treating
ovarian cancer, in particular those pertaining to the extended
release of an antineoplastic agent from biodegradable
poly(phosphoester) compositions.
[0003] 2. Description of the Prior Art
[0004] Antineoplastic agents, such as paclitaxel, have sometimes
been used to treat ovarian cancer. For example, those in the art
have attempted to administer paclitaxel in normal saline by
infusion into the peritoneal cavity of women having ovarian cancer
as a prolonged series of weekly treatments. Francis et al., "Phase
I Feasibility and Pharmacologic Study of Weekly Intraperitoneal
Paclitaxel: A Gynecologic Oncology Group Pilot Study", J. of
Clinical Oncology, 13:12, 2961-67 (1995). However, problems with
multiple toxicities, such as abdominal pain, nausea, vomiting,
leukopenia, and fatigue, are often encountered with the high fluid
volumes and drug dosages required for efficacy with this approach.
Further, the repeated dosing and attendant discomfort is often
inconvenient and, sometimes, even unacceptable for patients.
[0005] Thus, there exists a need for a method of effecting the in
vivo, controlled release of a variety of different antineoplastic
agents into the peritoneum, whether they are small hydrophobic
drugs, such as paclitaxel, or large and bulky bio-macromolecules,
such as therapeutically useful proteins. Preferably, effective
release of the antineoplastic agent should occur without requiring
the presence of significant amounts of a physiologically acceptable
fluid vehicle, such as normal saline or an organic solvent. There
is also a continuing need for biodegradable polymer compositions
that may provide extended release in such a way that trauma to the
surrounding soft tissues can be minimized.
[0006] Biocompatible polymeric materials have been used in various
therapeutic drug delivery and medical implant applications. If a
medical implant is intended for use as a drug delivery or other
controlled-release system, using a biodegradable polymeric carrier
is one effective means to deliver the therapeutic agent locally and
in a controlled fashion, see Langer et al., "Chemical and Physical
Structures of Polymers as Carriers for Controlled Release of
Bioactive Agents", J. Macro. Science, Rev. Macro. Chem. Phys.,
C23(1), 61-126 (1983). In this way, less total drug is required,
and toxic side effects can be minimized.
[0007] Polymers have been used for some time as carriers of
therapeutic agents to effect a localized and sustained release. See
Leong et al., "Polymeric Controlled Drug Delivery", Advanced Drug
Delivery Rev., 1:199-233 (1987); Langer, "New Methods of Drug
Delivery", Science, 249:1527-33 (1990) and Chien et al., Novel Drug
Delivery Systems (1982). Such delivery systems offer the potential
of enhanced therapeutic efficacy and reduced overall toxicity.
Examples of classes of synthetic polymers that have been studied as
possible solid biodegradable materials include polyesters (Pitt et
al., "Biodegradable Drug Delivery Systems Based on Aliphatic
Polyesters: Applications to Contraceptives and Narcotic
Antagonists", Controlled Release of Bioactive Materials, 19-44
(Richard Baker ed., 1980); poly(amino acids) and pseudo-poly(amino
acids) (Pulapura et al. "Trends in the Development of Bioresorbable
Polymers for Medical Applications", J. Biomaterials Appl., 6:1,
216-50 (1992); polyurethanes (Bruin et al., "Biodegradable Lysine
Diisocyanate-based Poly(Glycolide-co-.epsilon.
Caprolactone)-Urethane Network in Artificial Skin", Biomaterials,
11:4, 291-95 (1990); polyorthoesters (Heller et al., "Release of
Norethindrone from Poly(Ortho Esters)", Polymer Engineering Sci.,
21:11, 727-31 (1981); and polyanhydrides (Leong et al.,
"Polyanhydrides for Controlled Release of Bioactive Agents",
Biomaterials 7:5, 364-71 (1986).
[0008] Polymers having phosphate linkages, called poly(phosphates),
poly(phosphonates) and poly(phosphites), are known. See Penczek et
al., Handbook of Polymer Synthesis, Chapter 17:
"Phosphorus-Containing Polymers", (Hans R. Kricheldorf ed., 1992).
The respective structures of these three classes of compounds, each
having a different side chain connected to the phosphorus atom, are
as follows: 3
[0009] The versatility of these polymers comes from the versatility
of the phosphorus atom, which is known for a multiplicity of
reactions. Its bonding can involve the 3p orbitals or various 3s-3p
hybrids; spd hybrids are also possible because of the accessible d
orbitals. Thus, the physico-chemical properties of the
poly(phosphoesters) can be readily changed by varying either the R
or R' group. The biodegradability of the polymer is due primarily
to the physiologically labile phosphoester bond in the backbone of
the polymer. By manipulating the backbone or the side chain, a wide
range of biodegradation rates are attainable.
[0010] An additional feature of poly(phosphoesters) is the
availability of functional side groups. Because phosphorus can be
pentavalent, drug molecules or other biologically active substances
can be chemically linked to the polymer. For example, drugs with
-O-carboxy groups may be coupled to the phosphorus via a
phosphoester bond, which is hydrolyzable. See, Leong, U.S. Pat.
Nos. 5,194,581 and 5,256,765. The P--O--C group in the backbone
also lowers the glass transition temperature of the polymer and,
importantly, confers solubility in common organic solvents, which
is desirable for easy characterization and processing.
[0011] Copending U.S. application Ser. No. 09/053,648 and WO
98/44021 disclose biodegradable terephthalate
polyester-poly(phosphate) compositions; U.S. application Ser. No.
09/053,649 and WO 98/44020 disclose biodegradable compositions
containing polymers chain-extended by phosphoesters; and U.S.
application Ser. No. 09/070,204 and International Application No.
PCT/U.S. Pat. No. 98/09185 disclose biodegradable compositions
comprising poly(cycloaliphatic phosphoester) compounds. However,
none of these disclosures suggests the specific use of
biodegradable poly(phosphoester) compositions for treating ovarian
cancer specifically.
[0012] Thus, there remains a need for new methods and materials for
the difficult problem of successfully treating ovarian cancer with
a minimum of discomfort, toxicities and prolonged, periodic
re-dosing.
SUMMARY OF THE INVENTION
[0013] It has now been discovered that biodegradable polymer
compositions comprising:
[0014] (a) at least one antineoplastic agent and
[0015] (b) a biodegradable polymer comprising the recurring
monomeric units shown in formula I: 4
[0016] wherein
[0017] X is --O-- or --NR.sup.4--, where R.sup.4 is H or alkyl;
[0018] Y is --O--, --S-- or --NR.sup.4--;
[0019] each of R.sup.1 and R.sup.2 is a divalent organic
moiety;
[0020] L is a divalent, branched or straight chain aliphatic group
having 1-20 carbon atom, a cycloaliphatic group, or a group having
the formula: 5
[0021] R.sup.3 is selected from the group consisting of H, alkyl,
alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy; and
[0022] n is about 5-5,000;
[0023] are suitable for intraperitoneal administration to treat a
mammalian subject having ovarian cancer. These polymer compositions
provide extended release of the antineoplastic agent within the
peritoneum of the subject. Moreover, the polymer composition of the
invention increases the median survival rate from the cancer by at
least about 10%, as compared with the median survival rate obtained
by administration of a composition comprising the same dosage of
the antineoplastic agent without the biodegradable polymer of the
invention.
[0024] The invention also comprises a solid article suitable for
insertion into the peritoneum to treat a mammalian subject having
ovarian cancer, the article comprising a biodegradable polymer
composition comprising:
[0025] (a) at least one antineoplastic agent and
[0026] (b) a biodegradable polymer comprising the recurring
monomeric units shown above in formula I.
[0027] In yet another embodiment of the invention, a method is
provided for treating a mammalian subject having ovarian cancer by
the extended release of an antineoplastic agent, the method
comprising the steps of:
[0028] (a) combining the antineoplastic agent with a biodegradable
polymer having the recurring monomeric units shown above in formula
I to form a composition; and
[0029] (b) inserting the composition in vivo into the peritoneum of
the subject, such that the inserted composition is in at least
partial contact with an ovarian cancer tumor,
[0030] wherein the median survival rate from the cancer is
increased by at least about 10%, as compared with the median
survival rate obtained by administration of a composition
comprising the same dosage of the antineoplastic agent without the
biodegradable polymer.
[0031] The compositions of the invention can be used to deliver a
wide variety of antineoplastic agents, for example, from
hydrophobic drugs, such as paclitaxel, to large water-soluble
macromolecules, such as proteins, over an extended period of time
without necessitating significant volumes of a delivery fluid. The
methods of the invention can thus be used to significantly increase
the time period over which an effective dose of the antineoplastic
agent is released and increases the survival time of subjects
treated by the method to an unexpected degree. Further, the serious
disease of ovarian cancer can be therapeutically managed with a
minimum of side effects and without the unpleasantness and
discomfort of a periodic series of parenteral treatments
introducing significant amounts of fluid into the peritoneum.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1A shows the .sup.1H-NMR spectrum, and
[0033] FIG. 1B shows the .sup.31P-NMR spectrum for P(BHET-EOP/TC,
80/20).
[0034] FIG. 2 shows the FT-IR spectrum for P(BHET-EOP/TC,
80/20).
[0035] FIG. 3A shows the molecular weights and elemental analyses
for P(BHET-EOP/TC, 80/20) and P(BHET-HOP/TC, 90/10), and
[0036] FIG. 3B shows the GPC chromatogram for P(BHET-EOP/TC,
80/20).
[0037] FIG. 4A shows the DSC curve of P(BHET-EOP/TC, 80/20),
and
[0038] FIG. 4B shows the DSC curve of P(BHET-EOP/TC, 50/50).
[0039] FIGS. 5A and 5B show the in vitro degradation data for
P(BHET-EOP/TC, 80/20) and P(BHET-EOP/TC, 85/15).
[0040] FIG. 6 shows the change in molecular weight of P(BHDPT-EOP)
and P(BHDPT-EOP/TC) poly(phosphoesters) during in vitro
degradation.
[0041] FIGS. 7A and 7B show the in vivo degradation of
P(BHET-EOP/TC) in terms of weight or mass loss;
[0042] FIG. 7C shows the controlled delivery of hydrophobic small
molecules, such as paclitaxel, from a p(BHET-EOP/TC, 80/20)
film.
[0043] FIG. 8 shows an electron microscopic photograph of
P(BHET-EOP/TC, 80/20) microspheres containing FITC-BSA.
[0044] FIG. 9A shows the effect of loading level on the release
kinetics of FITC-BSA from microspheres, and
[0045] FIG. 9B shows the controlled delivery of hydrophobic small
molecules, such as paclitaxel from a CHDM polymer.
[0046] FIG. 10 shows the release of lidocaine from copolymer
P(BHDPT-EOP/TC) microspheres.
[0047] FIG. 11 shows the cytotoxicity of P(BHET-EOP/TC, 80/20)
microspheres.
[0048] FIG. 12 shows a toxicity assay plot of relative cell growth
(%) vs. concentration of degraded polymer in a tissue-culture well
(mg/ml) for four separate polymers.
[0049] FIG. 13 shows the cytotoxicity of P(BHET-EOP/TC, 80/20)
microspheres.
[0050] FIG. 14 shows the .sup.1H-NMR spectrum of a polymer of the
invention, P(LAEG-EOP).
[0051] FIG. 15 shows the .sup.31P-NMR spectrum of a polymer of the
invention, P(LAEG-EOP).
[0052] FIGS. 16A and 16B show differential scanning calorimetry
data for two polymers of the invention.
[0053] FIG. 17 shows the results of a GPC analysis of a polymer of
the invention in graphic form.
[0054] FIG. 18 shows the change in Mw of two polymers of the
invention after being exposed to air at room temperature for one
month.
[0055] FIG. 19 shows shelf stability data for a polymer of the
invention at room temperature.
[0056] FIGS. 20A and 20B show the weight loss (21A) and the change
in Mw (21B) for discs fabricated from two polymers of the invention
over a period of eight days in PBS at 37.degree. C.
[0057] FIGS. 21A and 21B show the weight loss (22A) and the change
in Mw (22B) for discs fabricated from two polymers of the
invention, in vitro.
[0058] FIG. 22 shows biocompatibility data for polymers of the
invention.
[0059] FIG. 23 shows cytotoxicity data for microspheres of a
polymer of the invention, P(LAEG-EOP).
[0060] FIG. 24A shows the effect of fabrication method upon the
release rate of microspheres of a polymer of the invention, and
[0061] FIG. 24B shows the rate of release of lidocaine from
microspheres of a polymer of the invention.
[0062] FIGS. 25(A) through 25(E) all show degradation and release
data of p(DAPG-EOP) polymers in vitro.
[0063] FIG. 26 shows the structure of P(trans-CHDM-HOP) as
determined by .sup.31P-NMR and .sup.1H-NMR.
[0064] FIG. 27 shows the chromatogram and molecular weight
distribution for P(cis-/trans-CHDM-HOP).
[0065] FIG. 28A graphically represents the active energy as a
function of frequency of P(trans-CHDM-HOP), and
[0066] FIG. 28B shows the corresponding viscosity.
[0067] FIG. 29A shows HEK293 cells grown on a P(CHDM-HOP) surface
after 72 hours of incubation, and
[0068] FIG. 29B shows HEK293 cells grown on a TCPS surface after 72
hours' incubation.
[0069] FIG. 30 graphically represents the effect of the side chain
structure on the in vitro degradation rate of three
poly(phosphoesters) of the invention in phosphate buffer
solution.
[0070] FIG. 31 shows the release curves of the bio-macromolecule
FITC-BSA from the polymer P(CHDM-HOP) at 33% loading.
[0071] FIG. 32 graphically represents the in vitro release kinetics
of FITC-BSA as a function of a loading levels of 30%, 10% and
1%.
[0072] FIG. 33 graphically represents the in vitro effect of side
chain structure on the protein release kinetics of FITC-BSA with a
10% loading level.
[0073] FIG. 34 shows the release of low molecular weight drugs
(doxorubicin, cisplatin, and 5-fluorouracil) from P(CHDM-HOP).
[0074] FIG. 35 shows the calibration curves for the release of IL-2
from a P(CHDM-HOP) matrix in tissue culture medium.
[0075] FIG. 36 shows the distribution of tumor sizes in mice four
weeks after tumor implantation in an in vivo melanoma tumor
model.
[0076] FIG. 37 shows the distribution of tumor sizes in mice six
weeks after tumor implantation in an in vivo melanoma tumor
model.
[0077] FIG. 38 shows the percentage of survival as a function of
time for four different treatment groups in an in vivo melanoma
tumor model.
[0078] FIG. 39 shows the release curves of two polymer compositions
of the invention, one comprising the chemotherapeutic agent
paclitaxel in the polymer P(CHDM-EOP) and the other comprising
paclitaxel in the polymer P(CHDM-HOP).
[0079] FIG. 40 shows the efficacy of paclitaxel in a solvent and
paclitaxel in a p(DAPG-EOP) polymer in an ovarian cancer animal
model (OVCAR3).
[0080] FIG. 41 shows the efficacy of p(DAPG-EOP) containing
paclitaxel in an OVCAR3 ovarian cancer animal model.
[0081] FIG. 42 shows the efficacy of p(DAPG-EOP) containing
paclitaxel in an OVCAR3 ovarian cancer animal model.
[0082] FIG. 43 shows further efficacy data for p(DAPG-EOP)
containing paclitaxel in an OVCAR3 ovarian cancer animal model.
[0083] FIG. 44 shows still further efficacy data for p(DAPG-EOP)
containing paclitaxel in an OVCAR3 ovarian cancer animal model.
DETAILED DESCRIPTION OF THE INVENTION
[0084] Polymeric Compositions of the Invention
[0085] As used herein, the expression "a mammalian subject" refers
to any mammalian subject, such as mice, rats, guinea pigs, cats,
dogs, human beings, cows, horses, sheep, or other livestock. The
expression "a mammalian subject having ovarian cancer" includes,
but is not limited to, subjects suffering from current symptoms of
this disease; subjects who are recovering from other modes of
treatment for the disease, such as surgery, chemotherapy, or other
treatment; and subjects simply believed to be at greater than
average risk for ovarian cancer, such as those who have at least
partially recovered from the disease in the past or those subjects
having a significant number of female relatives diagnosed as having
or having had the disease.
[0086] As used herein, the term "treating" includes:
[0087] (i) preventing a disease, disorder or condition from
occurring in an animal which may be predisposed to the disease,
disorder and/or condition but has not yet been diagnosed as having
it;
[0088] (ii) inhibiting the disease, disorder or condition, i.e.,
arresting its development; and
[0089] (iii) relieving the disease, disorder or condition, i.e.,
causing regression of the disease, disorder and/or condition.
[0090] The term "laliphatic" refers to a linear, branched or cyclic
alkane, alkene, or alkyne. Preferred linear or branched aliphatic
groups in the poly(cycloaliphatic phosphoester) composition of the
invention have from about 1 to 20 carbon atoms. Preferred
cycloaliphatic groups may have one or more sites of unsaturation,
i.e., double or triple bonds, but are not aromatic in nature.
[0091] As used herein, the term "aryl" refers to an unsaturated
cyclic carbon compound with 4n+2.pi. electrons. As used herein, the
term "heterocyclic" refers to a saturated or unsaturated ring
compound having one or more atoms other than carbon in the ring,
for example, nitrogen, oxygen or sulfur. "Heteroaryl" refers to a
heterocyclic compound with 4n+2 electrons.
[0092] As used herein, the term "non-interfering substituent" means
a substituent that does react with the monomers; does not catalyze,
terminate or otherwise interfere with the polymerization reaction;
and does not react with the resulting polymer chain through intra-
or inter-molecular reactions.
[0093] The biodegradable and injectable polymer composition of the
invention comprises a polymer having the recurring monomeric units
shown in formula I: 6
[0094] wherein X is --O-- or --NR.sup.4--, where R.sup.4 is H or
alkyl, such as methyl, ethyl, 1,2-dimethylethyl, n-propyl,
isopropyl, 2-methylpropyl, 2,2-dimethylpropyl or tert-butyl,
n-pentyl, tert-pentyl, n-hexyl, n-heptyl and the like.
[0095] The group Y in formula I is --O--, --S-- or --NR.sup.1--,
where R.sup.4 is as defined above.
[0096] Each of R.sup.1 and R.sup.2 can be any divalent organic
moiety, which may be either unsubstituted or substituted with one
or more non-interfering substituents, so long as the moiety and its
substituents do not interfere undesirably with the polymerization,
copolymerization, or biodegradation reactions of the polymer.
Specifically, each of R.sup.1 and R.sup.2 can be a branched or
straight chain aliphatic group, preferably having about 1-20 carbon
atoms. For example, R.sup.1 and R.sup.2 can be alkylene, such as
methylene, ethylene, 1-methylethylene, 1,2-dimethylethylene,
n-propylene, isopropylene, 2-methylpropylene,
2,2'-dimethylpropylene or tert-butylene, n-pentylene,
tert-pentylene, n-hexylene, n-heptylene, n-octylene, n-nonylene,
n-decylene, n-undecylene, n-dodecylene, and the like.
[0097] R.sup.1 and R.sup.2 can also be alkenylene, such as
ethenylene, propenylene, 2-vinylpropenylene, n-butenylene,
3-ethenylbutylene, n-pentenylene, 4-(3-propenyl)hexylene,
n-octenylene, 1-(4-butenyl)-3-methyldecylene, dodecenylene,
2-(3-propenyl)dodecylene, hexadecenylene, and the like. R.sup.1 and
R.sup.2 can also be alkynylene, such as ethynylene, propynylene,
3-(2-ethynyl)pentylene, n-hexynylene, octadecenynylene,
2-(2-propynyl)decylene, and the like.
[0098] R.sup.1 and R.sup.2 can also be an aliphatic group, such as
an alkylene, alkenylene or alkynylene group, substituted with a
non-interfering substituent, for example, a hydroxy, halogen or
nitrogen group. Examples of such groups include, but are not
limited to, 2-chloro-n-decylene, 1-hydroxy-3-ethenylbutylene,
2-propyl-6-nitro-10-dod- ecynylene and the like.
[0099] Further, R.sup.1 and R.sup.2 can be a cycloaliphatic group,
such as cyclopentylene, 2-methylcyclopentylene, cyclohexylene,
cyclohexenylene and the like. Each of R.sup.1 and R2 can also be a
divalent aromatic group, such as phenylene, benzylene, naphthalene,
phenanthrenylene, and the like, or a divalent aromatic group
substituted with a non-interfering substituent. Further each of
R.sup.1and R.sup.2 can be a divalent heterocyclic group, such as
pyrrolylene, furanylene, thiophenylene,
alkylene-pyrrolylene-alkylene, pyridylene, pyridinylene,
pyrimidinylene and the like, or may be any of these substituted
with a non-interfering substituent.
[0100] Preferably, R.sup.1 and R.sup.2 have from about 1-20 carbon
atoms and are an alkylene group, a cycloaliphatic group, a
phenylene group, or a divalent group having the formula: 7
[0101] wherein Z is oxygen, nitrogen, or sulfur, and m is 1 to 3.
More preferably, each of R.sup.1 and R2 is a branched or straight
chain alkylene group having from 1 to 7 carbon atoms. Most
preferably, each of R.sup.1 and R.sup.2 is a methylene, ethylene
group, n-propylene, 2-methyl-propylene, or a 2,2'-dimethylpropylene
group.
[0102] In one embodiment of the invention, either R.sup.1, R.sup.2
or both R.sup.1 and R.sup.2, can be an antineoplastic agent in a
form capable of being released in a physiological environment. When
the antineoplastic agent part of the poly(phosphoester) backbone in
this way, it is released as the polymeric matrix formed by the
composition of the invention degrades.
[0103] L in the polymer composition of the invention can be any
divalent, branched or straight chain aliphatic group having 1-20
carbon atom, a cycloaliphatic group, or a group having the formula:
8
[0104] When L is a branched or straight chain alkylene group, it is
preferably an alkylene group having from 1 to 7 carbon atoms, such
as 2-methylmethylene or ethylene. When L is a cycloaliphatic group,
it may be any divalent cycloaliphatic group so long as it does not
interfere with the polymerization or biodegradation reactions of
the polymer of the composition. Specific examples of useful
unsubstituted and substituted cycloaliphatic L groups, include
cycloalkylene groups such as cyclopentylene,
2-methylcyclopentylene, cyclohexylene, 2-chlorocyclohexylene, and
the like; cycloalkenylene groups, such as cyclohexenylene; and
cycloalkylene groups having fused or bridged additional ring
structures on one or more sides, such as tetralinylene,
decalinylene, and norpinanylene; or the like.
[0105] R.sup.3 in the polymer composition of the invention is
selected from the group consisting of H, alkyl, alkoxy, aryl,
aryloxy, heterocyclic and heterocycloxy residues.
[0106] When R.sup.3 is alkyl or alkoxy, it preferably contains
about 1 to about 20 carbon atoms, even more preferably about 1 to
about 15 carbon atoms and, most preferably about 1-7 carbon atoms.
Examples of such groups include methyl, methoxy, ethyl, ethoxy,
n-propyl, isopropoxy, n-butoxy, t-butyl, --C.sub.8H.sub.17; alkyl
substituted with a non-interfering substituent, such as halogen,
alkoxy or nitro; alkyl conjugated to a biologically active
substance to form a pendant drug delivery system; and the like.
[0107] When R.sup.3 is aryl or the corresponding aryloxy group, it
typically contains from about 5 to about 14 carbon atoms,
preferably about 5 to 12 carbon atoms and, optionally, can contain
one or more rings that are fused to each other. Examples of
particularly suitable aromatic groups include phenyl, phenoxy,
naphthyl, anthracenyl, phenanthrenyl and the like.
[0108] When R.sup.3 is heterocyclic or heterocycloxy, it typically
contains from about 5 to 14 ring atoms, preferably from about 5 to
12 ring atoms, and one or more heteroatoms. Examples of suitable
heterocyclic groups include furan, thiophene, pyrrole, isopyrrole,
3-isopyrrole, pyrazole, 2-isoimidazole, 1,2,3-triazole,
1,2,4-triazole, oxazole, thiazole, isothiazole, 1,2,3-oxadiazole,
1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole,
1,2,3,4-oxatriazole, 1,2,3,5-oxatriazole, 1,2,3-dioxazole,
1,2,4-dioxazole, 1,3,2-dioxazole, 1,3,4-dioxazole,
1,2,5-oxatriazole, 1,3-oxathiole, 1,2-pyran, 1,4-pyran, 1,2-pyrone,
1,4-pyrone, 1,2-dioxin, 1,3-dioxin, pyridine, N-alkyl pyridinium,
pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine,
1,2,3-triazine, 1,2,4-oxazine, 1,3,2-oxazine, 1,3,5-oxazine,
1,4-oxazine, o-isoxazine, p-isoxazine, 1,2,5-oxathiazine,
1,2,6-oxathiazine, 1,4,2-oxadiazine, 1,3,5,2-oxadiazine, azepine,
oxepin, thiepin, 1,2,4-diazepine, indene, isoindene, benzofuran,
isobenzofuran, thionaphthene, isothionaphthene, indole, indolenine,
2-isobenzazole, 1,4-pyrindine, pyrando[3,4-b]-pyrrole, isoindazole,
indoxazine, benzoxazole, anthranil, 1,2-benzopyran,
1,2-benzopyrone, 1,4-benzopyrone, 2,1-benzopyrone, 2,3-benzopyrone,
quinoline, isoquinoline, 12,-benzodiazine, 1,3-benzodiazine,
naphthpyridine, pyrido[3,4-b]-pyridine, pyrido[3,2-b]-pyridine,
pyrido[4,3-b]pyridine, 1,3,2-benzoxazine, 1,4,2-benzoxazine,
2,3,1-benzoxazine, 3,1,4-benzoxazine, 1,2-benzisoxazine,
1,4-benzisoxazine, carbazole, xanthrene, acridine, purine, and the
like. Preferably, when R.sup.3 is heterocyclic or heterocycloxy, it
is selected from the group consisting of furan, pyridine,
N-alkylpyridine, 1,2,3- and 1,2,4-triazoles, indene, anthracene and
purine rings.
[0109] In a particularly preferred embodiment, R.sup.3 is an alkyl
group, an alkoxy group, a phenyl group, a phenoxy group, or a
heterocycloxy group and, even more preferably, an alkoxy group
having from 1 to 10 carbon atoms. Most preferably, R.sup.3 is an
ethoxy or hexyloxy group.
[0110] Alternatively, the side chain R.sup.3 can be the
antineoplastic agent or some other biologically active substance
pendently attached to the polymer backbone, for example by ionic or
covalent bonding. In this pendant system, the antineoplastic agent
or other biologically active substance is released as the bond
connecting R.sup.3 with the phosphorous atom is cleaved under
physiological conditions.
[0111] The number "n" can vary greatly depending on the
biodegradability and the release characteristics desired in the
polymer, but typically varies between about 5 and 1,000.
Preferably, n is from about 5 to about 500 and, most preferably, is
from about 5 to about 200.
[0112] When used in accordance with the method of the invention,
the polymer composition provides extended release of the
antineoplastic agent into the peritoneum of a subject having
ovarian cancer, preferably for a period greater than one week, more
preferably for a period greater than two weeks. Even more
preferably, this time extends for a period greater than about three
weeks and, most preferably, is for a period greater than four
weeks, for example, from four weeks to a year.
[0113] Further, use of the composition in accordance with the
method of the invention increases the median survival rate from the
cancer by at least about 10%, as compared with the median survival
rate obtained by administration of a composition comprising the
same dosage of antineoplastic agent without the biodegradable
polymer of the invention. Preferably, the median survival rate is
increased by at least about 20%, more preferably by at least 30%
and, most preferably, by a factor of at least about 40%.
[0114] The polymer used in the composition of the invention is
preferably selected from the group consisting of: 9
[0115] wherein R.sup.1, R.sup.2, R.sup.3 and n are as defined
above.
[0116] In polymers of formula II, R.sup.5 is selected from the same
groups as for R.sup.1 and R.sup.2, and L is preferably a group
having the formula: 10
[0117] The molar ratio of x:y in formula II can vary greatly
depending on the desired solubility of the polymer, the desired
glass transition temperature (Tg), the desired stability of the
polymer, the desired stiffness of the final polymers, and the
biodegradability and the release characteristics desired in the
polymer. However, the molar ratio of x:y typically varies between
about 20:0 and 1:20. When y is 0, the polymer formed is a
homopolymer. Preferably, however, the ratio x:y is from about 1:15
to about 15:1, more preferably, from about 10:1 to about 1:1.
[0118] The most common way of controlling the molar ratio of x:y is
to vary the feed ratio of the "x" portion to the "y" portion when
synthesizing the polymer. Feed ratios can easily vary from 99: to
1:99, for example, 95:5, 90:10, 85:15, 80:20, 75:25, 70:30, 65:35,
60:40, 55:45, 50:50, 45:55, 20:80, 15:85, and the like. Preferably,
the monomer feed ratio varies from about 90:10 to about 50:50, even
more preferably from about 80:20 to about 50:50 and, most
preferably, from about 80:20 to about 50:50.
[0119] Preferably, when the biodegradable polymer has formula II,
R.sup.3 is alkoxy, aryloxy or heterocycloxy; x is about 0.1 to 30,
more preferably about 0.2 to 20, most preferably >1 (for
example, about 2-20); and y is 2.
[0120] In preferred polymers of formula III and IV: III 11
[0121] M.sup.1 and M.sup.2 are each independently (1) a branched or
straight chain aliphatic group having from about 1-20 carbon atoms,
even more preferably from about 1-7 carbon atoms; or (2) a branched
or straight chain, oxy-, carboxy- or amino-aliphatic group having
from about 1-20 carbon atoms, such as ethoxylene,
2-methylethoxylene, propoxylene, butoxylene, pentoxylene,
dodecyloxylene, hexadecyloxylene, and the like;
[0122] each of x and y is about 1 to 1,000;
[0123] the molar ratio of x:y can vary greatly depending on the
biodegradability and the release characteristics desired in the
polymer but, typically, is about 1;
[0124] the molar ratio n:(x or y) can vary greatly depending on the
biodegradability and the release characteristics desired in the
polymer, but typically varies between about 200:1 and 1:200,
preferably 100:1 and 1:100, more preferably from about 50:1 to
about 1:50; and
[0125] the molar ratio q:r can also vary greatly depending on the
biodegradability and the release characteristics desired in the
polymer, but typically varies between about 1:200 and 200:1,
preferably between about 1:150 to about 150:1 and, most preferably,
between about 1:99 and 99:1.
[0126] In formula III, each of Ml and L preferably h from 1 to 7
carbon atoms. More preferably, Ml is an ethylene group or a
methyl-substituted methylene group, and L is an ethylene group.
[0127] In formula IV, each of M.sup.1 and M.sup.2 is preferably a
branched or straight chain alkylene or alkoxylene group, more
preferably having from 1-20 carbon atoms. Even more preferably, at
least one of Ml and M.sup.2 is an alkylene or alkoxylene group
having a formula selected from the group consisting of
--(CH.sub.2).sub.a--, --(CH.sub.2).sub.a--O--, and
--(CH.sub.2).sub.a--O--(CH.sub.2).sub.b--, wherein each of a and b
is 1-7.
[0128] When either M.sup.1 and M.sup.2 is a branched or straight
chain, oxy-aliphatic group having from 1-20 carbon atoms it can
also be, for example, a dioxyalkylene group such as such as
dioxymethylene, dioxyethylene, 1,3-dioxypropylene,
2-methoxy-1,3-dioxypropylene, 1,3-dioxy-2-methylpropylene,
dioxy-n-pentylene, dioxy-n-octadecylene, methoxylene-methoxylene,
ethoxylene-methoxylene, ethoxylene-ethoxylene,
ethoxylene-1-propoxylene, butoxylene-n-propoxylene,
pentadecyloxylene-methoxylene, and the like. When M.sup.1 and
M.sup.2 is a branched or straight chain, dioxo-aliphatic group,
preferably it has the formula --O--(CH.sub.2).sub.a--O-- or
--O--(CH.sub.2).sub.a--O--(CH.s- ub.2).sub.b--, wherein each of a
and b is from 1-7.
[0129] When either M.sup.1 or M.sup.2 is a branched or straight
chain, carboxy-aliphatic group having from 1-20 carbon atoms, it
can also be, for example, a divalent carboxylic acid ester such as
the divalent radical corresponding to methyl formate, methyl
acetate, ethyl acetate, n-propyl acetate, isopropyl acetate,
n-butyl acetate, ethyl propionate, allyl propionate, t-butyl
acrylate, n-butyl butyrate, vinyl chloroacetate, 2-methoxycarbonyl
cyclohexanone, 2-acetoxycyclohexanone, and the like. When M.sup.1
or M.sup.2 is a branched or straight chain, carboxy-aliphatic
group, it preferably has the formula --CHR'--CO--O--CHR"--, wherein
R' and R" are each independently H, alkyl, alkoxy, aryl, aryloxy,
heterocyclic or heterocycloxy.
[0130] When either M.sup.1 or M.sup.2 is a branched or straight
chain, amino-aliphatic group having from 1-20 carbon atoms, it can
be a divalent amine such as --CH.sub.2NH--, --(CH.sub.2).sub.2N--,
--CH.sub.2(C.sub.2H.sub.5)N--, --n--C.sub.4H.sub.9--NH--,
--t--C.sub.4H.sub.9--NH--, --CH.sub.2 (C.sub.3H.sub.6)N--,
--C.sub.2H.sub.5(C.sub.3H.sub.6)N--, --CH.sub.2
(C.sub.8H.sub.17)N--, and the like. When M.sup.1 or M.sup.2 is a
branched or straight chain, amino-aliphatic group, it preferably
has the formula --(CH.sub.2).sub.a--NR' where R' is H or lower
alkyl, and "a" is from 1 to 7.
[0131] Preferably, M.sup.1 and/or M.sup.2 is an alkylene group
having the formula --O--(CH.sub.2) where a is 1 to 7 and, most
preferably, is a divalent ethylene group. In another particularly
preferred embodiment, M.sup.1 and M.sup.2 are n-pentylene and the
divalent radical corresponding to methyl acetate respectively.
[0132] In a preferred embodiment, L in formulas III and IV is a
branched or straight chain aliphatic group having from 1-20 carbon
atoms, more preferably an alkylene group having from 1 to 7 carbon
atoms, such as ethylene or methyl-substituted methylene.
[0133] In another particularly preferred polymer of formula IV,
M.sup.1 and M.sup.2 are each an alkylene or alkoxylene group; L is
an alkylene group; X is --O--; and R.sup.3 is an alkoxy group. Most
preferably, the biodegradable polymer used in the invention
comprises the recurring monomeric units shown in formula VI: 12
[0134] wherein the molar ratio of x:y is about 1;
[0135] the molar ratio n:(x or y) is between about 200:1 and 1:200;
and
[0136] n is about 5-5,000.
[0137] When the polymer used has formula V: 13
[0138] preferably, each of R.sup.1 and R.sup.2 is independently
straight or branched aliphatic, such as a branched or straight
chain alkylene group having from 1 to 7 carbon atoms, for example
methylene or ethylene, either unsubstituted or substituted with one
or more non-interfering substituents;
[0139] L is a divalent cycloaliphatic group, such as cyclohexylene,
either unsubstituted or substituted with a non-interfering
substituent;
[0140] R.sup.3 is selected from the group consisting of H, alkyl,
alkoxy, aryl, aryloxy, heterocyclic or heterocycloxy (preferably
alkoxy such as ethoxy or hexyloxy); and
[0141] n is about 5-5,000, even more preferably 5 to 500.
[0142] The molecular weight of the polymer used in the composition
of the invention can vary widely, depending on whether a rigid
solid state (higher molecular weights) desirable, or whether a
flowable or flexible state (lower molecular weights) is desired.
Generally, however, weight-average molecular weights (Mw) typically
vary from about 2,000 to about 400,000 daltons, preferably from
about 2,000 to about 200,000 daltons and, even more preferably,
from about 2,000 to 60,000 daltons. Most preferably, the Mw varies
between about 10,0000 to 55,000. Number-average molecular weight
(Mn) can also vary widely, but generally fall in the range of about
1,000 to about 200,000 daltons, preferably from about 1,000 to
about 100,000 daltons and, even more preferably, from about 1,000
to about 50,000 daltons. Most preferably, Mn varies between about
8,000 and 45,000 daltons.
[0143] A preferred method to determine molecular weight is by gel
permeation chromatography ("GPC"), e.g., mixed bed columns,
CH.sub.2Cl.sub.2 solvent, light scattering detector, and off-line
dn/dc.
[0144] The glass transition temperature (Tg) of the polymer used in
the invention can vary widely depending upon the degree of
branching in R.sup.1 and R.sup.2, the relative proportion of
phosphorous-containing monomer used to make the polymer, and the
like. When the article of the invention is a rigid solid, the Tg is
preferably within the range of from about -10.degree. C. to about
80.degree. C., even more preferably between about 0 and 50.degree.
C. and, most preferably between about 25.degree. C. to about
35.degree. C.
[0145] In other embodiments, the Tg is preferably low enough to
keep the composition of the invention flowable at body temperature.
Then, the glass transition temperature of the polymer used in the
invention is preferably about 0 to about 37.degree. C., more
preferably from about 0 to about 25.degree. C.
[0146] The biodegradable polymer used in the invention is
preferably sufficiently pure to be biocompatible itself and remains
biocompatible upon biodegradation. By "biocompatible", it is meant
that the biodegradation products or the polymer itself are
non-toxic and result in only minimal tissue irritation when
injected or placed into intimate contact with vasculated tissues.
The requirement for biocompatibility is more easily accomplished
because the presence of an organic solvent is not required in the
polymer composition of the invention.
[0147] However, the polymer used in the invention is preferably
soluble in one or more common organic solvents for ease of
synthesis, purification and handling. Common organic solvents
include such solvents as ethanol, chloroform, dichloromethane
(dimethylene chloride), acetone, ethyl acetate, DMAC, N-methyl
pyrrolidone, dimethylformamide, and dimethylsulfoxide. The polymer
is preferably soluble in at least one of the above solvents.
[0148] The polymer of the invention can also comprise additional
biocompatible monomeric units so long as they do not interfere with
the biodegradable characteristics and the desirable flow
characteristics of the invention. Such additional monomeric units
may offer even greater flexibility in designing the precise release
profile desired for targeted drug delivery or the precise rate of
biodegradability desired for other applications. When such
additional monomeric units are used, however, they should be used
in small enough amounts to insure the production of a biodegradable
copolymer having the desired physical characteristics, such as
rigidity, viscosity, flowability, flexibility or a particular
morphology.
[0149] Examples of such additional biocompatible monomers include
the recurring units found in other poly(phosphoesters),
poly(lactides), poly(glycolides), poly(caprolactones),
poly(anhydrides), poly(amides), poly(urethanes), poly(esteramides),
poly(orthoesters), poly(dioxanones), poly(acetals), poly(ketals),
poly(carbonates), poly(orthocarbonates), poly(phosphazenes),
poly(hydroxybutyrates), poly(hydroxy-valerates), poly(alkylene
oxalates), poly(alkylene succinates), poly(malic acids), poly(amino
acids), poly(vinylpyrrolidone), poly(ethylene glycol),
poly(hydroxycellulose), chitin, chitosan, and copolymers,
terpolymers, or combinations or mixtures of the above
materials.
[0150] When additional monomeric units are used, those which have a
lower degree of crystallization and are more hydrophobic are
preferred. Especially preferred recurring units with the desired
physical characteristics are those derived from poly(lactides),
poly(caprolactones), and copolymers of these with glycolide, in
which there are more amorphous regions.
[0151] General Synthesis of Phosphoester Polymers
[0152] The most common general reaction in preparing
poly-(phosphates) is a dehydrochlorination between a
phosphorodichloridate and a diol according to the following
equation: 14
[0153] Most poly(phosphonates) are also obtained by condensation
between appropriately substituted dichlorides and diols.
[0154] Poly(phosphites) have been prepared from glycols in a
two-step condensation reaction. A 20% molar excess of a
dimethylphosphite is used to react with the glycol, followed by the
removal of the methoxyphosphonyl end groups in the oligomers by
high temperature.
[0155] An advantage of melt polycondensation is that it avoids the
use of solvents and large amounts of other additives, thus making
purification more straightforward. It can also provide polymers of
reasonably high molecular weight. Somewhat rigorous conditions,
however, are often required and can lead to chain acidolysis (or
hydrolysis if water is present). Unwanted, thermally-induced side
reactions, such as crosslinking reactions, can also occur if the
polymer backbone is susceptible to hydrogen atom abstraction or
oxidation with subsequent macroradical recombination.
[0156] To minimize these side reactions, the polymerization can
also be carried out in solution. Solution polycondensation requires
that both the prepolymer and the phosphorus component be soluble in
a common solvent. Typically, a chlorinated organic solvent is used,
such as chloroform, dichloromethane, or dichloroethane.
[0157] A solution polymerization is preferably run in the presence
of equimolar amounts of the reactants and a stoichiometric amount
of an acid acceptor, usually a tertiary amine such as pyridine or
triethylamine. Reaction times tend to be longer with solution
polymerization than with melt polymerization. However, because
overall milder reaction conditions can be used, side reactions are
minimized, and more sensitive functional groups can be incorporated
into the polymer. Moreover, attainment of high molecular weights is
less likely with solution polymerization.
[0158] Interfacial polycondensation can be used when high reaction
rates are desired. The mild conditions used minimize side
reactions, and there is no need for stoichiometric equivalence
between the diol and dichloridate starting materials as in solution
methods. However, hydrolysis of the acid chloride may occur in the
alkaline aqueous phase. Sensitive dichloridates that have some
solubility in water are generally subject to hydrolysis rather than
polymerization. Phase transfer catalysts, such as crown ethers or
tertiary ammonium chloride, can be used to bring the ionized diol
to the interface to facilitate the polycondensation reaction. The
yield and molecular weight of the resulting polymer after
interfacial polycondensation are affected by reaction time, molar
ratio of the monomers, volume ratio of the immiscible solvents, the
type of acid acceptor, and the type and concentration of the phase
transfer catalyst.
[0159] The purpose of the polymerization reaction is to form a
polymer comprising (i) divalent organic recurring units and (ii)
phosphoester recurring units. The result can be a homopolymer, a
relatively homogeneous copolymer, or a block copolymer that has a
somewhat heterogeneous microcrystalline structure. Any one of these
three embodiments is well-suited for use as a controlled release
medium.
[0160] While the process may be in bulk, in solution, by
interfacial polycondensation, or any other convenient method of
polymerization, preferably, the process takes place under solution
conditions. Particularly useful solvents include methylene
chloride, chloroform, tetrahydrofuran, dimethyl formamide, dimethyl
sulfoxide, toluene, or any of a wide variety of other inert organic
solvents.
[0161] Particularly when solution polymerization reaction is used,
an acid acceptor is advantageously present during the
polymerization reaction. A particularly suitable class of acid
acceptor comprises tertiary amines, such as pyridine,
trimethylamine, triethylamine, substituted anilines and substituted
aminopyridines. The most preferred acid acceptor is the substituted
aminopyridine 4-dimethylaminopyridine ("DMAP").
[0162] In a particularly preferred embodiment of the invention, for
example, the biodegradable polymer of formula III or IV is made by
a process comprising the steps of:
[0163] (a) reacting at least one heterocyclic ring compound having
formula VII, VIII or IX: 15
[0164] wherein M.sup.1, M.sup.2 and X are as defined above, with an
initiator having the formula:
H--Y--L--Y--H,
[0165] wherein Y and L are as defined as above, to form a
prepolymer of formula X or XI, shown below: 16
[0166] wherein X, M.sup.1, M.sup.2, Y, L, R, x, y, q and r are as
defined above; and
[0167] (b) further reacting the prepolymer with a
phosphorodihalidate of formula XII: 17
[0168] where "halo" is Br, Cl or I; and R.sup.3 is as defined
above, to form a polymer of formula III or IV.
[0169] The function of the first reaction step (a) is to use the
initiator to open the ring of the heterocyclic ring compound of
formula VII, VIII or IX. Examples of useful heterocyclic compounds
of formula VII, VIII or IX include caprolactones, caprolactams,
amino acid anhydrides such as glycine anhydride, cycloalkylene
carbonates, dioxanones, glycolids, lactides and the like.
[0170] When the compound of the invention has formula III, only one
heterocyclic ring compound of formula VII, which contains Ml, may
be used to prepare the prepolymer in step (a). When the compound of
the invention has formula IV, then a combination of a heterocyclic
compound of formula VII, which contains M.sup.1, and a heterocyclic
compound of formula VIII, which contains M.sup.2 may be used in
step (a). Alternatively, when the compound of the invention has
formula IV, a single heterocyclic compound of formula IX, which
contains both M.sup.1 and M.sup.2 can be used in step (a).
[0171] Examples of suitable initiators include a wide variety of
compounds having at least two active hydrogens (H--Y--L--Y--H)
where L is a linking group and is defined above, and Y can be
--O--, --S-- or --NR.sup.4, where R.sup.4 is as defined above. The
linking group L is can be a straight chain group, e.g., alkylene,
but it may also be substituted with one or more additional
active-hydrogen-containing groups. For example, L may be a straight
chain alkylene group substituted with one or more additional alkyl
groups, each bearing a activated hydrogen moiety, such as --OH,
--SH, or NH.sub.2. In this way, various branched polymers can be
prepared using the branched active hydrogen initiators to design
the resulting polymer such that it has the desired properties.
However, when branched polymers are reacted with acid chlorides,
cross-linked polymers will result.
[0172] The reaction step (a) can take place at widely varying
temperatures, depending upon the solvent used, the molecular weight
desired, the susceptibility of the reactants to form side
reactions, and the presence of a catalyst. Preferably, however, the
reaction step (a) takes place at a temperature from about 0 to
about +235.degree. C. for melt conditions. Somewhat lower
temperatures may be possible with the use of either a cationic or
anionic catalyst.
[0173] While the reaction step (a) may be in bulk, in solution, by
interfacial polycondensation, or any other convenient method of
polymerization, preferably, the reaction step (a) takes place under
melt conditions.
[0174] Examples of particularly useful prepolymers of formula X
include:
[0175] (i) OH-terminated prepolymer derived from
polycaprolactone
H--[--O(CH.sub.2).sub.5--CO--].sub.x--O--CH.sub.2--CH.sub.2--O--[--CO--(CH-
.sub.2).sub.5--O--].sub.y--H;
[0176] (ii) NH-terminated prepolymer derived from polycaprolactam
(Nylon 6)
H--[--NH--(CH.sub.2).sub.5--CO--].sub.x--NH--CH.sub.2--CH.sub.2--NH--[--CO-
--(CH.sub.2).sub.5--NH--].sub.y--H;
[0177] (iii) OH-terminated prepolymer derived from polylactide
[0178]
H--[--OCH(CH.sub.3)--CO--].sub.x--O--CH.sub.2--CH.sub.2--O--[--CO---
CH(CH3)--O--].sub.y--H ;
and
[0179] (iv) OH-terminated prepolymer derived from polytrimethylene
carbonate
H--[--O(CH.sub.2).sub.3--O--CO--].sub.x--O--CH.sub.2--CH.sub.2--O--[--CO---
O--(CH.sub.2).sub.3--O--].sub.y--H.
[0180] Examples of particularly useful prepolymers of formula XI
include:
[0181] (i) OH-terminated copolymer derived from lactide and
glycolide: 18
[0182] (ii) OH-terminated copolymer derived from lactide and
caprolactone: 19
[0183] and
[0184] (iii) OH-terminated copolymer derived from glycolide and
caprolactone: 20
[0185] The purpose of the polymerization of step (b) is to form a
polymer comprising (i) the prepolymer produced as a result of step
(a) and (ii) interconnecting phosphorylated units. The result can
be a block copolymer having a microcrystalline structure that is
particularly well-suited to use as a controlled release medium.
[0186] The polymerization step (b) of the invention usually takes
place at a slightly lower temperature than the temperature of step
(a), but also may vary widely, depending upon the type of
polymerization reaction used, the presence of one or more
catalysts, the molecular weight desired, and the susceptibility of
the reactants to undesirable side reaction. When melt conditions
are used, the temperature may vary from about 0-150.degree. C.
However, when the polymerization step (b) is carried out in a
solution polymerization reaction, it typically takes place at a
temperature between about -40 and 100.degree. C.
[0187] Antineoplastic Agent
[0188] Generally speaking, the antineoplastic agent of the
invention can vary widely depending upon the pharmacological
strategy selected for inhibiting, destroying, or preventing the
ovarian cancer. The antineoplastic agent may be described as a
single entity or a combination of entities. The compositions,
articles and methods are designed to be used with antineoplastic
agents having high water-solubility, as well as those having low
water-solubility, to produce a delivery system that has controlled
release rates.
[0189] The term antineoplastic agent includes, without limitation,
alkylating agents, such as carboplatin and cisplatin; nitrogen
mustard alkylating agents; nitrosourea alkylating agents, such as
carmustine (BCNU); antimetabolites, such as methotrexate; purine
analog antimetabolites; pyrimidine analog antimetabolites, such as
fluorouracil (5-FU) and gemcitabine; hormonal antineoplastics, such
as goserelin, leuprolide, and tamoxifen; natural antineoplastics,
such as aldesleukin, interleukin-2, docetaxel, etoposide (VP-16),
interferon alfa, paclitaxel, and tretinoin (ATRA); antibiotic
natural antineoplastics, such as bleomycin, dactinomycin,
daunorubicin, doxorubicin, and mitomycin; and vinca alkaloid
natural antineoplastics, such as vinblastine and vincristine.
Preferably, the antineoplastic agent is selected from the group
consisting of paclitaxel, BCNU, carboplatin and cisplatin. Most
preferably, the antineoplastic agent is paclitaxel.
[0190] Further, the following additional drugs may also be used in
combination with the antineoplastic agent, even if not considered
antineoplastic agents themselves: dactinomycin; daunorubicin HCl;
docetaxel; doxorubicin HCl; epoetin alfa; etoposide (VP-16);
ganciclovir sodium; gentamicin sulfate; interferon alfa; leuprolide
acetate; meperidine HCl; methadone HCl; ranitidine HCl; vinblastin
sulfate; and zidovudine (AZT). For example, fluorouracil has
recently been formulated in conjunction with epinephrine and bovine
collagen to form a particularly effective combination.
[0191] Still further, the following listing of amino acids,
peptides, polypeptides, proteins, polysaccharides, and other large
molecules may also be used: interleukins 1 through 18, including
mutants and analogues; interferons or cytokines, such as
interferons .alpha., .beta., and .gamma.; hormones, such as
luteinizing hormone releasing hormone (LHRH) and analogues and,
gonadotropin releasing hormone (GnRH); growth factors, such as
transforming growth factor-.beta. (TGF-.beta.), fibroblast growth
factor (FGF), nerve growth factor (NGF), growth hormone releasing
factor (GHRF), epidermal growth factor (EGF), fibroblast growth
factor homologous factor (FGFHF), hepatocyte growth factor (HGF),
and insulin growth factor (IGF); tumor necrosis factor-.alpha.
& .beta. (TNF-.alpha. & .beta.); invasion inhibiting
factor-2 (IIF-2); bone morphogenetic proteins 1-7 (BMP 1-7);
somatostatin; thymosin-.alpha.-1; .beta.-globulin; superoxide
dismutase (SOD); complement factors; anti-angiogenesis factors;
antigenic materials; and pro-drugs.
[0192] In particularly preferred embodiment, the composition of the
invention may comprise other biologically active substances,
preferably a therapeutic drug or pro-drug, for example, other
chemotherapeutic agents, antibiotics, anti-virals, anti-fungals,
anti-inflammatories, and anticoagulants, antigens useful for cancer
vaccine applications or corresponding pro-drugs.
[0193] Various forms of the antineoplastic agents and/or other
biologically active agents may be used. These include, without
limitation, such forms as uncharged molecules, molecular complexes,
salts, ethers, esters, amides, and the like, which are biologically
activated when implanted, injected or otherwise placed into the
body.
[0194] In a particularly preferred embodiment, a biodegradable
polymer composition suitable for intraperitoneal administration to
treat a mammalian subject having ovarian cancer comprises:
[0195] (a) paclitaxel and
[0196] (b) a biodegradable polymer comprising the recurring
monomeric units shown in formula VI: 21
[0197] wherein the molar ratio of x:y is about 1;
[0198] the molar ratio n:(x or y) is between about 200:1 and 1:200;
and
[0199] n is about 5-5,000.
[0200] Biodegradation and Release Characteristics
[0201] Biodegradable polymers differ from non-biodegradable
polymers in that they can be degraded during in vivo therapy. This
generally involves breaking down the polymer into its monomeric
subunits. In principle, the ultimate hydrolytic breakdown products
of the polymer used in the invention are a cycloaliphatic diol, an
aliphatic alcohol and phosphate. All of these degradation products
are potentially non-toxic. However, the intermediate oligomeric
products of the hydrolysis may have different properties. Thus, the
toxicology of a biodegradable polymer intended for insertion into
the body, even one synthesized from apparently innocuous monomeric
structures, is typically determined after one or more toxicity
analyses.
[0202] There are many different ways of testing for toxicity and/or
biocompatibility known to those of ordinary skill in the art. A
typical in vitro toxicity assay, however, would be performed with
live carcinoma cells, such as GT3TKB tumor cells, in the following
manner:
[0203] Two hundred microliters of various concentrations of the
degraded polymer products are placed in 96-well tissue culture
plates seeded with human gastric carcinoma cells (GT3TKB3) at
10.sup.4/well density. The degraded polymer products are incubated
with the GT3TKB cells for 48 hours. The results of the assay can be
plotted as % relative growth vs. concentration of degraded polymer
in the tissue-culture well.
[0204] Polymers can also be evaluated by well-known in vivo
biocompatibility tests, such as by subcutaneous implantation or
injection in rats to confirm that the systems hydrolyze without
significant levels of irritation or inflammation at the insertion
site.
[0205] The polymer of formula I is usually characterized by a
biodegradation rate that is controlled at least in part as a
function of hydrolysis of the phosphoester bond of the polymer.
Other factors are also important. For example, the lifetime of a
biodegradable polymer in vivo also depends upon its molecular
weight, crystallinity, biostability, and the degree of
crosslinking. In general, the greater the molecular weight, the
higher the degree of crystallinity, and the greater the
biostability, the slower biodegradation will be. In addition, the
rate of degradation of the polymer can be further controlled by
choosing a side chain of differing lengths. Accordingly,
degradation times can very widely, preferably from less than a day
to several months.
[0206] Accordingly, the structure of the side chain can influence
the release behavior of compositions comprising a biologically
active substance. For example, it is expected that conversion of
the phosphate side chain to a more lipophilic, more hydrophobic or
bulky group would slow down the degradation process. Thus, release
is usually faster from polymer compositions with a small aliphatic
group side chain than with a bulky aromatic side chain.
[0207] The expression "extended release", as used herein, includes,
without limitation various forms of release, such as controlled
release, timed release, sustained release, delayed release, long
acing, and pulsatile delivery, immediate release that occurs with
various rates. The ability to obtain extended release, controlled
release, timed release, sustained release, delayed release, long
acting, pulsatile delivery or immediate release is performed using
well-known procedures and techniques available to the ordinarily
skilled artisan. None of these specific techniques or procedures
constitute an inventive aspect of this invention.
[0208] Polymer Compositions
[0209] The antineoplastic agents are used in amounts that are
therapeutically effective, which varies widely depending largely on
the particular antineoplastic agent being used. The amount of
antineoplastic agent incorporated into the composition also depends
upon the desired release profile, the concentration of the agent
required for a biological effect, and the length of time that the
biologically active substance has to be released for treatment.
Preferably, the biologically active substance is blended with the
polymer matrix of the invention at different loading levels,
preferably at room temperature and without the need for an organic
solvent.
[0210] There is no critical upper limit on the amount of
antineoplastic agent incorporated except for that of an acceptable
solution or dispersion viscosity to maintain the physical
characteristics desired for the composition. The lower limit of the
antineoplastic agent incorporated into the delivery system is
dependent upon the activity of the drug and the length of time
needed for treatment. Thus, the amount of the antineoplastic agent
should not be so small that it fails to produce the desired
physiological effect, nor so large that the antineoplastic agent is
released in an uncontrollable manner.
[0211] Typically, within these limits, amounts of the
antineoplastic agent from about 1% up to about 65% can be
incorporated into the present delivery systems. However, lesser
amounts may be used to achieve efficacious levels of treatment for
antineoplastic agent that are particularly potent.
[0212] In addition, the polymer composition of the invention can
also comprise blends of the polymer of the invention with other
biocompatible polymers or copolymers, so long as the additional
polymers or copolymers do not interfere undesirably with the
biodegradable or mechanical characteristics of the composition.
Blends of the polymer of the invention with such other polymers may
offer even greater flexibility in designing the precise release
profile desired for targeted drug delivery or the precise rate of
biodegradability desired. Examples of such additional biocompatible
polymers include other poly(phosphoesters), poly(carbonates),
poly(esters), poly(orthoesters), poly(amides), poly(urethanes),
poly(imino-carbonates), and poly(anhydrides).
[0213] Pharmaceutically acceptable polymeric carriers may also
comprise a wide range of additional materials. Without being
limited thereto, such materials may include diluents, binders and
adhesives, lubricants, disintegrants, colorants, bulking agents,
flavorings, sweeteners, and miscellaneous materials such as buffers
and adsorbents, in order to prepare a particular medicated
composition, with the condition that none of these additional
materials will interfere with the biocompatibility,
biodegradability and physical state desired of the polymer
compositions of the invention.
[0214] For delivery of an antineoplastic agent or some other
biologically active substance, the agent or substance is added to
the polymer composition. The agent or substance is either dissolved
to form a homogeneous solution of reasonably constant concentration
in the polymer composition, or dispersed to form a suspension or
dispersion within the polymer composition at a desired level of
"loading" (grams of biologically active substance per grams of
total composition including the biologically active substance,
usually expressed as a percentage).
[0215] While it is possible that the biodegradable polymer or the
biologically active agent may be dissolved in a small quantity of a
solvent that is non-toxic to more efficiently produce an amorphous,
monolithic distribution or a fine dispersion of the biologically
active agent in the flexible or flowable composition, it is an
advantage of the invention that, in a preferred embodiment, no
solvent is needed to form a flowable composition. Moreover, the use
of solvents is preferably avoided because, once a polymer
composition containing solvent is placed totally or partially
within the body, the solvent dissipates or diffuses away from the
polymer and must be processed and eliminated by the body, placing
an extra burden on the body's clearance ability at a time when the
illness (and/or other treatments for the illness) may have already
deleteriously affected it.
[0216] However, when a solvent is used to facilitate mixing or to
maintain the flowability of the polymer composition of the
invention, it should be non-toxic, otherwise biocompatible, and
should be used in minimal amounts. Solvents that are toxic clearly
should not be used in any material to be placed even partially
within a living body. Such a solvent also must not cause tissue
irritation or necrosis at the site of administration.
[0217] Examples of suitable biocompatible solvents, when used,
include N-methyl-2-pyrrolidone, 2-pyrrolidone, ethanol, propylene
glycol, acetone, methyl acetate, ethyl acetate, methyl ethyl
ketone, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran,
caprolactam, dimethyl-sulfoxide, oleic acid, or
1-dodecylazacycloheptan-2-one. Preferred solvents include
N-methyl-2-pyrrolidone, 2-pyrrolidone, dimethyl sulfoxide, and
acetone because of their solvating ability and their
biocompatibility.
[0218] The polymer composition of the invention may be a flexible
or flowable material. By "flowable" is meant the ability to assume,
over time, the shape of the space containing it at body
temperature. This includes, for example, liquid compositions that
are capable of being sprayed into a site; injected with a manually
operated syringe fitted with, for example, a 23-gauge needle; or
delivered through a catheter.
[0219] Also included by the term "flowable", however, are highly
viscous, "gel-like" materials at room temperature that may be
delivered to the desired site by pouring, squeezing from a tube, or
being injected with any one of the commercially available power
injection devices that provide injection pressures greater than
would be exerted by manual means alone for highly viscous, but
still flowable, materials. When the polymer used is itself
flowable, the polymer composition of the invention, even when
viscous, need not include a biocompatible solvent to be flowable,
although trace or residual amounts of biocompatible solvents may
still be present. The degree of viscosity of the polymer can be
adjusted by the molecular weight of the polymer, as well as by
mixing the cis- and trans-isomers of the cyclohexane dimethanol in
the backbone of the polymer.
[0220] The polymer composition of the invention can be administered
by a variety of routes. For example, if flowable, it can be
injected to form, after injection, a temporary biomechanical
barrier to coat or encapsulate internal organs or tissues. The
polymer composition of the invention can also be used to produce
coatings for solid implantable devices.
[0221] However, most importantly, the polymer composition of the
invention provides controllable and effective release of the
antineoplastic agent over time, even in the case of large
bio-macromolecules.
[0222] Implants and Delivery Systems
[0223] In its simplest form, a biodegradable polymer delivery
system consists of a solution or dispersion of an antineoplastic
agent in a polymer matrix having an unstable (biodegradable) bond
incorporated into the polymer backbone. In a particularly preferred
embodiment, a solid article comprising the composition of the
invention is inserted within the peritoneum by implantation,
injection, laparoscopy or otherwise being placed within the
peritoneum of the subject being treated, for example, during or
after the surgical removal of visibly cancerous tissue.
[0224] The antineoplastic agent of the composition and the polymer
may form a homogeneous matrix, or the biologically active substance
may be encapsulated in some way within the polymer. For example,
the biologically active substance may be first encapsulated in a
microsphere and then combined with the polymer in such a way that
at least a portion of the microsphere structure is maintained.
Alternatively, the biologically active substance may be
sufficiently immiscible in the polymer of the invention that it is
dispersed as small droplets, rather than being dissolved, in the
polymer.
[0225] As a structural medical device, the polymer compositions of
the inventions provide a wide variety of physical forms having
specific chemical, physical and mechanical properties suitable for
insertion into the peritoneum, in addition to being a composition
that degrades in vivo into non-toxic residues.
[0226] Biodegradable drug delivery articles can be prepared in
several ways The polymer can be melt processed using conventional
extrusion or injection molding techniques, or these products can be
prepared by dissolving in an appropriate solvent, followed by
formation of the device, and subsequent removal of the solvent by
evaporation or extraction, e.g., by spray drying. By these methods,
the polymers may be formed into articles of almost any size or
shape desired, for example, implantable solid discs or wafers or
injectable rods, microspheres, or other microparticles. Typical
medical articles also include such as implants as laminates for
degradable fabric or coatings to be placed on other implant
devices.
[0227] The antineoplastic agent is typically released from the
polymeric matrix at least as quickly as the matrix biodegrades in
vivo. With some antineoplastic agents, the agent will be released
only after the polymer has been degraded to a point where a
non-diffusing substance has been exposed to bodily fluids. As the
polymer begins to degrade, the biologically active substance that
was completely surrounded by the polymer matrix begins to be
liberated.
[0228] However, with this mechanism, a long peptide chain that is
physically entangled in a rigid solid implant structure may tend to
degrade along with the matrix and break off from the remainder of
the peptide chain, thereby releasing incomplete fragments of
molecules. When the polymer compositions of the invention are
designed to be flexible, however, the polymer will typically
degrade after the peptide or protein has been released in part. In
a particularly preferred mechanism, when a peptide chain is being
released from the composition of the invention, the composition
remains flexible and allows a large-molecule protein to, at least
partially, diffuse through the polymeric matrix prior to its own or
the polymer's biodegradation.
[0229] The initial release rate of proteins from the compositions
is therefore generally diffusion-controlled through channels in the
matrix structure, the rate of which is inversely proportional to
the molecular weight of the protein. Once polymer degradation
begins, however, the protein remaining in the matrix may also be
released by the forces of erosion.
[0230] The biodegradable amorphous matrices of the invention
typically contain polymer chains that are associated with other
chains. These associations can be created by a simple entanglement
of polymer chains within the matrix, as opposed to hydrogen bonding
or Van der Vaals interactions or between crystalline regions of the
polymer or interactions that are ionic in nature. Alternatively,
the synthesis of block copolymers or the blending of two different
polymers can be used to create viscous, "putty-like" materials with
a wide variation in physical and mechanical properties.
[0231] In a particularly preferred embodiment, the composition of
the invention is sufficiently flowable to be injected into the
body. It is particularly important that the injected composition
result in minimal tissue irritation after injection or otherwise
being inserted into the peritoneal cavity.
[0232] In one embodiment, the polymer composition of the invention
is used to form a soft, drug-delivery "depot" that can be
administered as a liquid, for example, by injection, but which
remains sufficiently viscous to maintain the drug within the
localized area around the injection site. The degradation time of
the depot so formed can be varied from several days to a year or
more, depending upon the polymer selected and its molecular weight.
By using a polymer composition in flowable form, even the need to
make an incision can be eliminated. In any event, the flexible or
flowable delivery "depot" will adjust to the shape of the space it
occupies within the body with a minimum of trauma to surrounding
tissues.
[0233] When the polymer composition of the invention is flexible or
flowable, it can be placed anywhere within the body, including a
cavity such as the peritoneum, sprayed onto or poured into open
wounds, or used as a site delivery system during surgery. When
flowable, the composition of the invention can also be used to act
as a temporary barrier in preventing the direct adhesion of
different types of tissue to each other, for example, after
abdominal surgery, due to its ability to encapsulate tissues,
organs and prosthetic devices.
[0234] Once inserted, the polymer composition of the invention
should remain in at least partial contact with a biological fluid,
such as blood, internal organ secretions, mucous membranes, and the
like. The implanted or injected composition will release the
antineoplastic agent contained within its matrix at a controlled
rate until the substance is depleted, following the general rules
for diffusion or dissolution from a rigid, flexible or flowable
biodegradable polymeric matrix.
[0235] The following examples are illustrative of preferred
embodiments of the invention and are not to be construed as
limiting the invention thereto. All polymer molecular weights are
average molecular weights. All percentages are based on the percent
by weight of the final delivery system or formulation being
prepared, unless otherwise indicated, and all totals equal 100% by
weight.
EXAMPLES
Example 1
[0236] Synthesis of Copolymer P(BHET-EOP/TC, 80/20) 22
[0237] Under an argon stream, 10 g of 1,4-bis(hydroxyethyl)
terephthalate (BHET), 9.61 g of 4-dimethylaminopyridine (DMAP), and
70 mL of methylene chloride were placed in a 250 mL flask equipped
with a funnel. The solution in the flask was cooled down to
-40.degree. C. with stirring, and a solution of 5.13 g of ethyl
phosphorodichloridate (EOP) (distilled before use) in 20 mL of
methylene chloride was added dropwise through the funnel. After
addition was complete, the mixture was stirred at room temperature
for four hours to form the homopolymer BHET-EOP.
[0238] A solution of 1.60 g of terephthaloyl chloride (TC)
(obtained from Aldrich Chemical Company and recrystallized with
hexane before use) in 20 mL of methylene chloride was then added
drop by drop. The temperature was brought up to about 45-50.degree.
C. gradually, and the reaction mixture was kept refluxing overnight
to complete the copolymerization of the homopolymer P(BHET-EOP)
with the additional monomer TC to form the copolymer
P(BHET-EOP/TC).
[0239] The solvent was then evaporated, and the residue was
redissolved in about 100-200 mL of chloroform. The chloroform
solution was washed with a saturated NaCl solution three times,
dried over anhydrous Na.sub.2SO.sub.4, and quenched into ether. The
resulting precipitate was redissolved in chloroform and quenched
again into ether. The resulting tough, off-white solid precipitate
was filtered off and dried under vacuum. Yield 82%.
[0240] The structure of P(BHET-EOP/TC, 80/20) was ascertained by
.sup.1H-NMR, .sup.31P-NMR and FT-IR spectra, as shown in FIGS. 1
and 2. The structure was also confirmed by elemental analysis,
which correlated closely with theoretical ratios. The results of
the elemental analysis are shown in FIG. 3.
[0241] The molecular weight of P(BHET-EOP/TC, 80/20) was first
measured by gel permeation chromatography (GPC) with polystyrene as
the calibration standard. The resulting graph established a weight
average molecular weight (Mw) of about 6100 and a number average
molecular weight (Mn) of about 2200, as shown in FIG. 4. Vapor
pressure osmometry ("VPO") for this copolymer gave an Mn value of
about 7900. The results of these molecular weight studies are also
shown in FIG. 3.
Example 2
[0242] Feed Ratio Variations of P(BHET-EOP/TC)
[0243] A series of other P(BHET-EOP/TC) copolymers of the invention
were prepared by following the procedure described above in Example
1 except that the feed ratio of the EOP to TC used during the
initial polymerization step and copolymerization step respectively
was varied. The results are shown below in Table 1. From the feed
ratio of EOP/TC, the value of "x" from the formula shown below can
be calculated. For example, in P(BHET-EOP/TC, 80/20) prepared above
in Example 1, x is 8.
1TABLE 1 23 Variation of Feed Ratio of EOP to TC in P(BHET-EOP/TC)
Feed Ratio of EOP/TC* 100/0 95/5 90/10 85/15 80/20 50:50 "x" -- 38
18 11.4 8 2 *Feed ratio of ethyl phosphorodichloridate to
terephthaloyl chloride.
Example 3
[0244] Synthesis and Isolation of the Homopolymer P(BHDPT-EOP)
24
[0245] The BHDPT monomer prepared in Example 5 above and the acid
acceptor 4-dimethylaminopyridine (DMAP) were dissolved in methylene
chloride. The resulting solution was chilled to -70.degree. C.
using a dry ice/acetone bath, and an equal molar amount of ethyl
phosphorodichloridate (EOP) was slowly added. The reaction mixture
was then heated and refluxed overnight. The salt formed in the
polymerization was removed by filtration. The remaining polymer
solution (filtrate) was washed with a saturated NaCl solution three
times, and the homopolymer was precipitated in diethyl ether.
Example 4
[0246] Synthesis of Copolymer P(BHDPT-EOP/TC) 25
[0247] Copolymers of P(BHDPT-EOP) with TC were synthesized by the
two-step solution copolymerization shown above. After the reaction
between BHDPT and EOP had proceeded at room temperature for one
hour, the reaction flask was cooled in a dry ice/acetone bath. An
appropriate amount of TC (the number of moles of TC and EOP
combined equaled the number of moles of BHDPT) was slowly added to
the flask. The reaction mixture was then heated and refluxed
overnight. The salt formed in the polymerization was removed by
filtration. The remaining copolymer solution (filtrate) was washed
with a saturated NaCl solution three times, and the copolymer was
precipitated out in diethyl ether.
Example 5
[0248] Synthesis of Poly(phosphoester) P(BHDPT-HOP/TC) 26
[0249] Copolymers of P(BHDPT-HOP) with TC were synthesized by a
two-step solution polymerization. After the reaction between BHDPT
and HOP had proceeded at room temperature for one hour, the
reaction flask was cooled in a dry ice/acetone bath. An appropriate
amount of TC (the number of moles of TC and HOP combined equaled
the number of moles of BHDPT) was slowly added to the flask. The
reaction mixture was then heated and refluxed overnight. The salt
formed during the copolymerization was removed by filtration. The
remaining copolymer solution (filtrate) was washed with a saturated
NaCl solution three times, and the copolymer was precipitated out
in diethyl ether.
Example 6
[0250] Other Diol Variations
[0251] Diol terephthalates that are structurally related to that of
BHET and BHDPT were synthesized by reacting TC with either
n-propylenediol or 2-methylpropylenediol, the structures of which
are shown below, to form the corresponding diol terephthalate.
--CH.sub.2CH.sub.2CH.sub.2--
[0252] 27
[0253] These diol terephthalates were then reacted with EOP to form
the corresponding homopolymers. The homopolymers so formed were
then used to produce the copolymers of the invention in a second
reaction with TC, as described above in Example 4.
Example 7
[0254] Glass Transition Temperatures for P(BHET-EOP/TC)
Copolymers
[0255] By differential scanning calorimetry (DSC), the glass
transition temperatures (Tg's) of P(BHET-EOP/TC, 80/20) and
P(BHET-EOP/TC, 50/50) were determined to be 24.5.degree. C. and
62.2.degree. C. respectively. FIG. 4 shows the DSC curves for these
two polymers. The Tg's of four additional P(BHET-EOP/TC) copolymers
of differing EOP/TC feed ratios were determined, and the results
were tabulated, as shown below in Table 2:
2TABLE 2 Glass Transition Temperatures (Tg's) of (BHET-EOP/TC)
Polymers Ratio of 100/0 95/5 90/10 85/15 80/20 50:50 EOP/TC* Tg
(.degree. C.) 19.1 20.7 21.2 29.8 24.5 62.2 *Feed ratio of ethyl
phosphorodichloridate to terephthaloyl chloride
[0256] The Tg increased as the proportion of EOP decreased and the
proportion of TC increased.
Example 8
[0257] Glass Transition Temperatures for P(BHDPT-EOP/TC)
Copolymers
[0258] A study of the influence of an increasing proportion of
terephthaloyl chloride (TC) on the Tg's of P(BHDPT-EOP/TC)polymers
was also conducted. The results are shown below in Table 3.
3TABLE 3 Influence of EOP/TC Ratio on the Tg of P (BHDPT-EOP/TC)
Molar ratio (BHDPT/EOP/TC)* Tg (.degree. C.) 100:100:0 14 100:100:0
19 100:90:10 16 100:85:15 24 100:80:20 23 100:75:25 33 100:75:25 49
100:50:50 43 *The total molar amount of TC and EOP equaled the
molar amount of BHDPT.
Example 9
[0259] Glass Transition Temperatures for Various R Groups
[0260] A study was also conducted showing the effect on glass
transition temperature (Tg) for copolymers made from the following
series of diols having varying R groups: 28
[0261] where R is --CH.sub.2CH.sub.2--;
--CH.sub.2CH.sub.2CH.sub.2--; --CH.sub.2CH(CH.sub.3)CH.sub.2--; and
--CH.sub.2CH(CH.sub.3).sub.2CH.sub.- 2--. The results are shown
below in Table 4:
4TABLE 4 Influence of the Changing "R" Group on Tg of Polymer "R"
Group Structure Tg (.degree. C.) ethylene --CH.sub.2CH.sub.2--
14-19 n-propylene --CH.sub.2CH.sub.2CH.sub.2-- -15 2-methyl-
propylene 29 11 2,2'-dimethyl- propylene 30 19
[0262] As shown in Table 4, the Tg increased as the size and the
degree of branching of the R group increased. In addition, the
polymers changed in physical state as the Tg changed. Specifically,
as Tg increased, the polymers changed from rubbery to fine
powders.
Example 10
[0263] Solubilities of the Polymers of the Invention
[0264] The solubility in organic solvents was determined for the
homopolymer P(BHET-EOP, 100/0) and for the following block
copolymers:
[0265] P(BHET-EOP/TC, 95/5),
[0266] P(BHET-EOP/TC, 90/10),
[0267] P(BHET-EOP/TC, 85/15),
[0268] P(BHET-EOP/TC, 80/20), and
[0269] P(BHET-EOP/TC, 50/50).
[0270] The organic solvents used for the test were chloroform,
methylene chloride, N-methylpyrrolidone (NMP), dimethylformamide
(DMF) and dimethylsulfoxide (DMSO). The results of these solubility
tests are summarized below in Table 5.
5 TABLE 5 Polymer CHCl.sub.3 CH.sub.2Cl.sub.2 NMP DMF DMSO P(BHET-
Easily Easily Good Good Good EOP soluble soluble solubi- solubi-
solubi- 100/0) lity lity lity P(BHET- Easily Easily Good Good Good
EOP/TC, soluble soluble solubi- solubi- solubi- 95/5) lity lity
lity P(BHET- Easily Easily Good Good Good EOP/TC, soluble soluble
solubi- solubi- solubi- 90/10) lity lity lity P(BHET- Rela- Rela-
Good Good Good EOP/TC, tively tively solubi- solubi- solubi- 85/15)
soluble soluble lity lity lity P(EHET- Rela- Rela- Good Good Good
EOP/TC, tively tively solubi- solubi- solubi- 80/20) soluble
soluble lity lity lity P(EHET- Not Not Soluble Soluble Soluble
EOP/TC, soluble soluble with with with 50/50) heating heating
heating
[0271] The results showed that the solubility of these polymers in
organic solvents increased as the EOP/TC ratio increased.
Example 11
[0272] Viscosities of the Polymers
[0273] The intrinsic viscosities of a series of P(BHET-EOP/TC)
polymers of varying feed ratios were measured in chloroform
(CH.sub.3Cl) at 40.degree. C. in a Ubbelohde viscometer. The
results are shown below in Table 6.
6TABLE 6 Intrinsic Viscosities of P(BHET-EOP/TC) Polymers Ratio of
100/0 95/5 90/10 85/15 80/20 50:50 EOP/TC* [.eta.] .081 .089 .148
.146 0.180 N.D..dagger. (dL/g) *Feed ratio of ethyl
phosphorodichloridate to terephthaloyl chloride. .dagger.The
intrinsic viscosity of P(BHET-EOP/TC, 50/50) was not determined
because it was not soluble in chloroform.
Example 12
[0274] In vitro Degradation
[0275] Films of P(BHET-EOP/TC, 80/20) and P(BHET-EOP/TC, 85/15)
were made by solution casting methods and were dried under vacuum
for two days. Discs 1 mm in thickness and 6 mm in diameter were cut
from these film sheets. Three discs of each copolymer were placed
in 4 mL of phosphate buffer saline (PBS) (0.1M, pH 7.4) at
37.degree. C. The discs were taken out of the PBS at different
points in time, washed with distilled water, and dried
overnight.
[0276] The samples were analyzed for change in molecular weight and
weight loss over time, as shown in FIGS. 7A and 7B. The weight
average molecular weight of P(BHET-EOP/TC, 80/20) decreased about
20% in three days. After 18 days, the P(BHET-EOP/TC, 85/15) and
P(BHET-EOP/TC, 80/20) discs had lost about 40% and 20% in mass
respectively.
[0277] This data demonstrated the feasibility of fine-tuning the
degradation rate of the copolymers and confirmed that the
copolymers became more hydrolytically labile as the phosphate
component (EOP) was increased.
[0278] The same process was repeated for the P(BHDPT-EOP)
copolymers having different feed ratios of EOP to TC. FIG. 6 is a
graphic representation of the degree of degradation, as measured by
change in molecular weight, over time for the homopolymer
P(BHDPT-EOP) and the following block copolymers:
[0279] P(BHDPT-EOP/TC, 85/15),
[0280] P(BHDPT-EOP/TC, 75/25), and
[0281] P(BHDPT-EOP/TC, 50/50).
Example 13
[0282] In vivo Degradation of P(BHET-EOP/TC) Copolymer and
Paclitaxel Release in vitro
[0283] FIGS. 7A and 7B shows the in vivo degradation of
P(BHET-EOP/TC, 80/20), as measured by weight loss. FIG. 7C shows
paclitaxel release from film in vitro.
Example 14
[0284] In vitro Biocompatability/Cytotoxicity of P(BHET-EOP/TC,
80/20)
[0285] The cytotoxicity of P(BHET-EOP/TC, 80/20) copolymer was
assessed by culturing human embryonic kidney (HEK) cells on a cover
slip that had been coated with the copolymer P(BHET-EOP/TC, 80/20).
As a control, HEK cells were also cultured on a coverslip coated
with TCPS. The cells cultured on the copolymer-coated cover slip
exhibited normal morphology at all times and proliferated
significantly in 72 days, as compared to a considerably lower
amount when identical HEK cells were cultured on TCPS.
Example 15
[0286] In vivo Biocompatibility of P(BHET-EOP/TC, 80/20)
[0287] A 100 mg polymer wafer was formed from P(BHET-EOP/TC, 80/20)
and, as a reference, a copolymer of lactic and glycolic acid
(75/25, "PLGA") known to be biocompatible. These wafers were
inserted between muscle layers of the right limb of adult SPF
Sprague-Dawley rats under anesthesia. The wafers were retrieved at
specific times, and the surrounding tissues were prepared for
histopathological analysis by a certified pathologist using the
following scoring:
7 Score Level of Irritation 0 No Irritation 0-200 Slight Irritation
200-400 Mild Irritation 400-600 Moderate Irritation More than 600
Severe Irritation
[0288] The results of the histopathological analysis are shown
below in Table 7.
8TABLE 7 Inflammatory Response at Site of Implantation (i.m.) 3 7
14 1 2 3 Polymer Days Days Days Mo. Mos. Mos. P(BHET- 151 116 163
98 60 35 EOP/TC, 80/20) PLGA 148 98 137 105 94 43 (75/25)
[0289] The phosphoester copolymer P(BHET-EOP/TC, 80/20) was shown
to have an acceptable biocompatability similar to that exhibited by
the PLGA reference wafer.
Example 16
[0290] Preparation of P(BHET-EOP/TC, 80/20) Microspheres
Encapsulating FITC-BSA
[0291] Microspheres were prepared via a
double-emulsion/solvent-extraction method using FITC-labeled bovine
serum albumin (FITC-BSA) as a model protein drug. One hundred .mu.L
of an FITC-2SA solution (10 mg/mL) were added to a solution of 100
mg of P(BHET-EOP/TC, 80/20) in 1 mL of methylene chloride, and
emulsified via sonication for 15 seconds on ice. The resulting
emulsion was immediately poured into 5 mL of a vortexing aqueous
solution of 1% polyvinyl alcohol (PVA) and 5% NaCl. The vortexing
was maintained for one minute. The resulting emulsion was poured
into 20 mL of an aqueous solution of 0.3% PVA and 5% NaCl, which
was being stirred vigorously. Twenty-five mL of a 2% isopropanol
solution was added, and the mixture was kept stirring for one hour
to ensure complete extraction. The resulting microspheres were
collected via centrifugation at 3000.times.g, washed three times
with water, and lyophilized. Empty microspheres were prepared in
the same way except that water was used as the inner aqueous
phase.
[0292] These preparation conditions had been optimized for
increased encapsulation efficiency, improved microsphere
morphology, and minimal burst release. The resulting microspheres
were mostly between 5 and 20 .mu.m in diameter and exhibited a
smooth surface morphology. FIG. 8 shows the size and smoothness of
the microspheres, as demonstrated by electron microscopy.
[0293] The loading level of FITC-BSA was determined by assaying for
FITC after hydrolyzing the microspheres in a 0.5 N NaOH solution
overnight. Loading levels were determined by comparison with a
standard curve, which had been generated by making a series of
FITC-BSA solutions in 0.5 N NaOH. Protein loading levels of 1.5,
14.1 and 22.8 wt. % were readily obtained.
[0294] The encapsulation efficiency of FITC-BSA by the microspheres
was determined at different loading levels by comparing the
quantity of FITC-BSA entrapped with the initial amount in solution
via fluorometry. As shown below in Table 8, encapsulation
efficiencies of 84.6 and 99.6% were obtained. These results showed
that encapsulation efficiencies of 70-90% would be readily
obtainable.
9TABLE 8 Encapsulation Efficiency and Loading Level of FITC-BSA in
P(BHET-EOP/TC, 80/20) High Low Loading Loading Loading (%) (22.8%)
(1.5%) Encapsulation 99.6 84.6 Efficiency (%)
[0295] In addition, it was determined by observation with confocal
fluorescence microscopy that the encapsulated FITC-BSA was
distributed uniformly within the microspheres.
Example 17
[0296] Preparation of P(BHDPT-EOP/TC, 50/50) Microspheres
Containing Lidocaine
[0297] An aqueous solution of 0.5% w/v polyvinyl alcohol (PVA) was
prepared in a 600 mL beaker by combining 1.35 g of PVA with 270 mL
of deionized water. The solution was stirred for one hour and
filtered. A copolymer/drug solution was prepared by combining 900
mg of P(BHDPT-EOP/TC, 50/50) copolymer and 100 mg of lidocaine in 9
mL of methylene chloride and vortex-mixing.
[0298] While the PVA solution was being stirred at 800 rpm with an
overhead mixer, the polymer/drug mixture was added dropwise. The
combination was stirred for one and a half hours. The microspheres
thus formed were then filtered, washed with deionized water, and
lyophilized overnight. The experiment yielded 625 mg of
microspheres loaded with 3.7% w/w lidocaine.
[0299] Lidocaine-containing microspheres were also prepared from
P(BHDPT-HOP/TC, 50/50) by the same process. This experiment yielded
676 mg of microspheres loaded with 5.3% w/w lidocaine.
Example 18
[0300] In vitro Release Kinetics of Microspheres Prepared from
P(BHET-EOP/TC, 80/20) Copolymers
[0301] Five mg of P(BHET-EOP/TC, 80/20) microspheres containing
FITC-BSA were suspended in one mL of phosphate buffer saline (PBS)
at pH 7.4 and placed into a shaker heated to a temperature of
37.degree. C. At various points in time, the suspension was spun at
3000.times.g for 10 minutes, and 500 .mu.l samples of the
supernatant fluid were withdrawn and replaced with fresh PBS. The
release of FITC-BSA from the microspheres was followed by measuring
the fluorescence intensity of the withdrawn samples at 519 nm.
[0302] Scaling up, 50 mg of P(BHET-EOP/TC, 80/20) microspheres were
suspended in vials containing 10 mL of phosphate buffer saline
(PBS). The vials were heated in an incubator to a temperature of
37.degree. C. and shaken at 220 rpm. Samples of the supernatant
were withdrawn and replaced at various points in time, and the
amount of FITC-BSA released into the samples was analyzed by
spectrophotometry at 492 nm.
[0303] The results indicated that over 80% of the encapsulated
FITC-BSA was released within the first two days, with an additional
amount of about 5% being released after 10 days in PBS at
37.degree. C. The release kinetics of FITC-BSA from P(BHET-EOP/TC,
80/20) microspheres at different loading levels are shown in FIG.
11.
Example 19
[0304] In vitro Release Kinetics of Microspheres Prepared from
P(BHDPT-EOP/TC, 50/50) Copolymers
[0305] Approximately 10 mg of P(BHDPT-EOP/TC, 50/50) microspheres
loaded with lidocaine were placed in PBS (0.1 M, pH 7.4) at
37.degree. C. on a shaker. Samples of the incubation solution were
withdrawn periodically, and the amount of lidocaine released into
the samples was assayed by HPLC. FIGS. 10 and 11 show the resulting
release kinetics.
[0306] The same process was followed for microspheres prepared from
P(BHDPT-HOP/TC, 50/50). FIGS. 10 and 11 also show the release
kinetics of lidocaine from these microspheres.
Example 20
[0307] In vitro Cytotoxicity Assay of Copolymer on Cells
[0308] P(BHET-EOP/TC, 80/20) microspheres were added to 96-well
tissue culture plates at different concentrations. The wells were
then seeded with human gastric carcinoma cells (GT3TKB) at a
density of 10.sup.4 cells/well. The cells were incubated with the
microspheres for 48 hours at 37.degree. C. The resulting cell
proliferation rate was analyzed by MTT assay and plotted as %
relative growth vs. concentration of copolymer microspheres in the
tissue culture well. The results are shown in FIG. 14.
Example 21
[0309] Toxicity Assay of Polymer-Degradation Products on GT3TKB
Tumor Cells
[0310] About 100-150 mg of each of the following polymers were
degraded separately in 20 mL of 1M NaOH at 37.degree. C. for 1-2
days:
[0311] PLLA (Mw=14,000)
[0312] P(BHET-EOP)
[0313] PCPP:SA (20:80)
[0314] Poly(L-lysine) (Mw =88,000)
[0315] Complete degradation was observed for all of the polymers.
The solution was then neutralized with 20 mL of 1M HCl.
[0316] About 200 .mu.L of various concentrations of the degraded
polymer products were placed in 96-well tissue culture plates and
seeded with human gastric carcinoma cells (GT3TKB) at a density of
10.sup.4/well. The degraded polymer products were incubated with
the GT3TKB cells for 48 hours. The results of the assay were
plotted as % relative growth vs. concentration of degraded polymer
in the tissue-culture well and are shown in FIG. 13.
[0317] An additional toxicity assay was conducted with microspheres
prepared from the monomer BHET and from the homopolymer BHET-EOP,
and compared with microspheres prepared from LA and PLLA. The
results of the assay were plotted as % relative growth vs.
concentration of the polymers or microspheres in a tissue-culture
cell and are shown in FIG. 14.
Example 22
[0318] Synthesis of Poly(L-lactide-co-ethyl-phosphate)
[Poly(LAEG-EOP)] 31
P(LAEG-EOP)
[0319] 20 g (0.139 mole of
(3S)-cis-3,6-dimethyl-1,4-dioxane-2,5-dione (L-lactide) (obtained
from Aldrich Chemical Company, recrystallized with ethyl acetate,
sublimed, and recrystallized with ethyl acetate again) and 0.432 g
(6.94 mmole) of ethylene glycol (99.8%, anhydrous, from Aldrich)
were placed in a 250 mL round-bottomed flask flushed with dried
argon. The flask was closed under vacuum and placed in an oven
heated to 140.degree. C. The flask was kept at this temperature for
about 48 hours with occasional shaking.
[0320] The flask was then filled with dried argon and placed in oil
bath heated to 135.degree. C. Under an argon stream, 1.13 g of
ethyl phosphorodichloridate was added with stirring. After one hour
of stirring, a low vacuum (about 20 mm Hg) was applied to the
system, and it was allowed to stand overnight. One hour before
work-up, a high vacuum was applied. After cooling, the polymer was
dissolved in 200 mL of chloroform and quenched into one liter of
ether twice to an off-white precipitate, which was dried under
vacuum.
[0321] It was confirmed by NMR spectroscopy that the polymer
obtained was the desired product,
poly(L-lactide-co-ethyl-phosphate) [P(LAEG-EOP)], as shown in FIGS.
6 and 7.
Example 23
Properties of P(LAEG-EOP)
[0322] A P(LAEG-EOP) polymer where (x or y)/n=10:1 was prepared as
described above in Example 22. The resulting
poly(phosphoester-co-ester) polymer was analyzed by GPC using
polystyrene as a standard, and the resulting graph established an
Mw of 33,000 and an Mn of 4800, as shown in FIG. 16.
[0323] The viscosity was measured in chloroform (CH.sub.3Cl) at
40.degree. C. and determined to be 0.315 dL/g. The polymer was
soluble in ethyl acetate, acetone, acetonitrile, chloroform,
dichloromethane, tetrahydrofuran, N-methylpyrrolidone,
dimethylformamide, and dimethyl sulfoxide. The polymer formed a
brittle film, and the Tg was determined by DSC to be 51.5.degree.
C., as shown in FIGS. 17A and 17B.
Example 24
[0324] Synthesis of Poly(L-lactide-co-hexyl-phosphate)
[Poly(LAEG-HOP)]
[0325] A second poly(L-lactide-phosphate) having the following
structure: 32
[0326] was also prepared by the method described in Example 22,
except that hexyl phosphorodichloridate ("HOP") was substituted for
EOP (ethyl phosphorodichloridate).
Example 25
[0327] Properties of P(LAEG-EOP) and P(LAEG-HOP)
[0328] The weight-average molecular weight (Mw) of the
phosphoester-co-ester polymer of Example 22, P(LAEG-EOP), and the
polymer of Example 24, P(LAEG-HOP), were first determined by gel
permeation chromatography (GPC) with polystyrene as the calibration
standard, as shown in FIG. 18. Samples of each were then allowed to
remain exposed to room temperature air to test for ambient,
unprotected storage capability. After one month, the Mw was again
determined for each polymer. The results (plotted in FIG. 19)
showed that, while the Mw for p(LAEG-EOP) was reduced by about
one-third after a month of unprotected ambient conditions, the Mw
for p(LAEG-HOP) remained fairly constant, even showing a slight
increase. See also FIG. 20.
[0329] Discs for degradation studies were then fabricated from each
polymer by compression molding at 50.degree. C. and a pressure of
200 MPa. The discs were 4 mm in diameter, 1.5 mm in thickness, and
40 mg in weight. The degradation studies were conducted by placing
the discs in 4 mL of 0.1M PBS (pH 7.4) at 37.degree. C. Duplicate
samples were removed at different time points up to eight days,
washed with distilled water, and dried under vacuum overnight.
Samples were analyzed for weight loss and molecular weight change
(GPC), and the results are shown in FIGS. 4A, 4B, 10A and 10B. Both
polymers, P(LAEG-EOP) and P(LAEG-HOP), demonstrated favorable
degradation profiles.
Example 26
[0330] In vivo Biocompatibility of P(LAEG-EOP)
[0331] A 100 mg polymer wafer was formed from P(LAEG-EOP) and, as a
reference, a copolymer of lactic and glycolic acid ["PLGA (RG755)"]
known to be biocompatible. These wafers were inserted between
muscle layers of the right limb of adult SPF Sprague-Dawley rats
under anesthesia. The wafers were retrieved at specific times, and
the surrounding tissues were prepared for histopathological
analysis by a certified pathologist using the following
scoring:
10 Score Level of Irritation 0 No Irritation 0-200 Slight
Irritation 200-400 Mild Irritation 400-600 Moderate Irritation More
than 600 Severe Irritation
[0332] The results of the histopathological analysis are shown
below in Table 9.
11TABLE 9 Inflammatory Response at Site of Implantation (i.m.) 3 7
14 1 2 3 Polymer Days Days Days Mo. Mos. Mos. P(LAEG- 130 123 180
198 106 99 EOP) PLGA 148 98 137 105 94 43 (RG755)
[0333] See also FIG. 23. The phosphoester copolymer P(LAEG-EOP) was
shown to have an acceptable biocompatability similar to that
exhibited by the PLGA reference wafer.
[0334] Similar tests were done after intramuscular injection of
microspheres into male S-D rats, tabulating implant site macrophage
counts, as well as irritation scores, as shown below:
12 3 Day 7 Day 14 Day 31 Day Ir- Ir- Ir- Ir- rita rita rita rita
Polymer # tion # tion # tion # tion p(BHET- 247 Mild 298 Mild 196
Sl. 32 Sl. EOP/TC) 80/20 p(BHET- 445 Mod. 498 Mod. 406 Mod. 38 Sl.
EOP/TC) 82.5/ 17.5 p(BHET- 161 Sl. 374 Mild 586 Mod. 274 Mild
EOP/TC) * 85/15 p(CHDM- 399 Mild 169 Sl. 762 Sev. 607 Sev. HOP)
p(BHET- 206 Mild 476 Mod. 557 Mod. 72 Sl. EOP/TC) 90/10 P(DAPG- 360
Mild 323 Mild 569 Mod. 96 Sl. EOP) 1:10 PLGA 419 Mod. 331 Mod. 219
Mild 150 Sl. (RG755) Control 219 Mild -- -- -- -- -- -- (no poly-
mer) # = Mean count * Only two animals present in this group.
[0335] Still further tests were done after subcutaneous injection
into male S-D rats, tabulating implant site macrophage counts, as
well as irritation scores, as shown below:
13 7 Day 14 Day 31 Day Ir- Ir- Ir- rita rita rita Group # tion #
tion # tion Vehicle only 0 -- 0 -- 0 -- (0.7 ml) (n = 3) Acetic
Acid 208 Mild 166 Sl. 20 Sl. (0.7 ml) (n = 3) p(d1) Lactic 302 Mild
37 Sl. 0 -- Acid (89 g/kg) (0.7 ml) (n = 3) p(DAPG-HOP) 355 Mild
192 Sl. 101 Sl. (89 mg/kg) (0.7 ml) (n = 6) p(CHDM-HOP) 652 Sev.
352 Mild 633 Sev. (89 mg/kg) (0.7 ml) (n = 6) P(BHET- 325 Mild 423
Mod. 197 Sl. EOP/TC) (89 mg/kg) (0.7 ml) (n = 6) Vehicle 65 Sl. 0
-- 0 -- (2.0 ml) (n = 3) Acetic Acid 267 Mild 334 Mild 32 Sl. (2.0
ml) (n = 3) p(d1) Lactic 85 Sl. 18 Sl. 279 Mild Acid (267 g/kg)
(2.0 ml) (n = 3) p(DAPG-HOP) 386 Mild 273 Mild 279 Mild (267 mg/kg)
(2.0 ml) (n = 6) p(CHDM-HOP) 471 Mod. 599 Mod. 618 Sev. (267 mg/kg)
(2.0 ml) (n = 6) P(BHET- 292 Mild 327 Mild 178 Sl. EOP/TC) (267
mg/kg) (2.0 ml) (n = 6) # = Mean count
Example 27
[0336] Preparation of Copolymer Microspheres Containing FITC-BSA
with 10% Theoretical Loading Level
[0337] One hundred mL of FITC-BSA solution (100 mg/mL dissolved in
water) was added to a solution of 100 mg of P(LAEG-EOP) in 1 mL of
methylene chloride, and emulsified via sonication for 15 seconds on
ice. The resulting emulsion was immediately poured into 5 mL of
vortexing a 1% solution of polyvinyl alcohol (PVA) in 5% NaCl, and
vortexing was maintained for one minute. The emulsion thus formed
was then poured into 20 mL of a 0.3% PVA solution in 5% NaCl, which
was being stirred vigorously. Twenty five mL of a 2% solution of
isopropanol was added, and the mixture was kept stirring for one
hour to ensure complete extraction. The resulting microspheres were
collected via centrifugation at 3000.times.g, washed 3 times with
water, and freeze dried.
[0338] Different formulations of microspheres were made by using as
the second aqueous phase a 5% NaCl solution or a 5% NaCl solution
also containing 1% PEG 8000. Yet another technique was used in
evaporating the solvent by stirring the mixture overnight, thus
forming microspheres by solvent evaporation.
Example 28
[0339] Estimation of Encapsulation Efficiency and Loading Level
[0340] The loading level of FITC-BSA was determined by assaying for
FITC after hydrolyzing the microspheres with 0.5 N NaOH overnight.
The amount of FITC-BSA was compared with a standard curve that had
been generated by making a series of FITC-BSA solutions in 0.5 N
NaOH. The encapsulation efficiency of the microspheres was
determined by comparing the quantity of FITC-BSA entrapped with the
initial amount in solution via fluorometry. The encapsulation
efficiency (%) and loading level (%) of FITC-BSA are shown in Table
10 below.
14TABLE 10 Encapsulation Efficiency and Loading Level of FITC-BSA
High Low Loading Loading Loading (%) (24.98%) (1.5%) Encapsulation
98.10 91.70 Efficiency (%)
Example 29
[0341] Cytotoxicity of the Copolymer
[0342] Microspheres containing P(LAEG-EOP) were added to 96-well
tissue culture plates at different concentrations. Human gastric
carcinoma cells (GT3TKB) were then seeded at a rate of 10.sup.4
cells/well. The cells were then incubated with the microspheres in
the wells for 48 hours at 37.degree. C. The cell proliferation rate
was analyzed by MTT assay, and the results were plotted as %
relative growth vs. concentration of copolymer microspheres in the
tissue culture well, as shown in FIG. 24.
Example 30
[0343] Effect of Fabrication Method on the Release of FITC-BSA from
Microspheres
[0344] Fifty mg of microspheres of a polymer of the invention were
suspended in vials containing 10 mL of PBS, and the vials were
shaken in an incubator at 37.degree. C. and at a rate of 220 rpm.
The supernatant fluid was replaced at various time points, and the
amount of FITC-BSA released was analyzed by spectrophotometry at
492 nm. The results were plotted as % cumulative release of
FITC-BSA from the microspheres vs. time in hours, as shown in FIG.
25.
Example 31
[0345] Preparation of P(LAEG-EOP) Microspheres Containing Lidocaine
Using Polyvinyl Alcohol as the Non-Solvent Phase
[0346] A solution of 0.5% w/v polyvinyl alcohol (PVA) in deionized
water solution was prepared in a 600 mL beaker by combining 1.05 g
of PVA with 210 mL of deionized water. The solution was stirred for
one hour and filtered. A polymer/drug solution was prepared by
combining 630 mg of polymer and 70 mg of lidocaine in 7 mL of
methylene chloride and mixing by vortex. The PVA solution was mixed
at 500 rpm with an overhead mixer, and the polymer/drug solution
was added dropwise. After 30 minutes of mixing, 200 mL of cold
deionized water was added to the stirring PVA solution. The
resulting mixture was stirred for a total of 3.5 hours. The
microspheres formed were filtered off, washed with deionized water,
and lyophilized overnight.
[0347] Microspheres loaded with 4.2% w/w lidocaine were thus
obtained. Approximately 10 mg of microspheres were placed in a
phosphate buffer saline (0.1M, pH 7.4) at 37.degree. C. on a shaker
and sampled regularly. The results were plotted as a lidocaine
released vs. time in days, as shown in FIG. 25.
Example 32
[0348] Synthesis of P(DAPG-EOP)
[0349] The d,l racemic mixture of
poly(L-lactide-co-propyl-phosphate) ["P(DAPG-EOP)"] was prepared as
follows: 33
[0350] The product was obtained as a white solid soluble in organic
solvents. Depending on reaction conditions, different intrinsic
viscosities and different molecular weights were obtained, as shown
below in summary form:
15 Reaction Base(s) Time/Temp Eq EOPCl.sub.2 Mw IV 3.0 eq 18 hrs/
1.05 -- 0.06 Reillex reflux 3.0 eq 40 hrs/ 1.05 -- 0.06 Reillex
reflux 3.0 eq 18 hrs/ 1.05 -- 0.08 Reillex& reflux 0.1% (w/w)
DMAP 3.0 eq 18 hrs/ 1.00 -- 0.06 Reillex reflux 2.5 eq 15 mins/
1.05 -- 0.42 TEA; 0.5 room eq DMAP temp. 2.5 eq 18 hrs/ 1.05 --
0.27 TEA; 0.5 reflux eq DMAP 2.5 eq about 2.5 1.05 -- 0.39 TEA; 0.5
days/ eq DMAP reflux 2.5 eq 1 h/4.degree. C.; 1.01 -- 0.06 TEA; 0.1
2 h/room eq DMAP temp. 2.5 eq 1 h/4.degree. C.; 1.01 91,100 0.47
TEA; 0.5 2 h/room eq DMAP temp. 2.5 eq 1 h/4.degree. C.; 1.01
95,900 0.42 TEA; 0.5 2 h/room (Mn eq DMAP temp. 44,200; Mw/Mn 2.2)
1.1 eq 1 h/4.degree. C.; 1.01 -- 0.08 DMAP 2 h/room temp. 1.5 eq 1
h/4.degree. C.; 1.01 -- 0.23 TEA; 0.5 2 h/room eq DMAP temp. 2.5 eq
1 h/4.degree. C.; 1.00 28,400 0.25 TEA; 0.5 17 h/room eq DMAP temp.
2.5 eq 1 h/4.degree. C.; 1.00 26,800 0.23 TEA; 0.5 2 h/room (Mn eq
DMAP temp. 12,900; Mw/Mn 2.1) 2.5 eq 1 h/4.degree. C.; 1.01 14,700
0.16 TEA; 0.5 2 h/room eq DMAP temp. 2.5 eq 1 h/4.degree. C.; 1.01
32,200 0.32 TEA; 0.5 2 h/room (Mn eq DMAP temp. 13,000; Mw/Mn 2.5)
3.0 eq 1 h/4.degree. C.; 1.00 -- 0.20 DMAP 2 h/room temp. 2.5 eq 1
h/4.degree. C.; 1.00 -- 0.22 TEA; 0.5 2 h/room eq DMAP temp.
Example 33
[0351] Preparation of P(DAEG-EOP) Microspheres With Lidocaine Using
Silicon Oil as the Non-solvent Phase
[0352] Two percent sorbitan-trioleate, which is commercially
available from Aldrich under the tradename Span-85, in silicon oil
was prepared in a 400 mL beaker by combining 3 mL of Span-85 with
150 mL of silicone oil and mixing with an overhead stirrer set at
500 rpm. A d,l racemic mixture of
poly(L-lactide-co-ethyl-phosphate) P(DAEG-EOP) polymer/drug
solution was prepared by dissolving 400 mg of the polymer prepared
above in Example 33, and 100 mg of lidocaine in 4.5 mL of methylene
chloride. The resulting polymer/drug solution was added dropwise to
the silicone oil/span mixture with stirring. The mixture was
stirred for an hour and 15 minutes. The microspheres thus formed
were filtered off and washed with petroleum ether to remove the
silicone oil/span mixture, and lyophilized overnight.
[0353] 450 mg of microspheres loaded with 7.6% w/w lidocaine were
thus obtained. Approximately 10 mg of microspheres were placed in
phosphate buffer saline (0.1M, pH 7.4) at 37.degree. C. on a shaker
and sampled regularly. The results were plotted as a lidocaine
released vs. time in days.
[0354] Similar data for P(DAPG-EOP) microspheres containing
paclitaxel was obtained, as shown in FIGS. 26A, 26B, 26C, 26D, 26E
and 26F.
Example 34
[0355] Biocompatibility of Poly(phosphoester) Microspheres in Mouse
Peritoneal Cavity
[0356] The biocompatibility of biodegradable poly(phosphoester)
microspheres of the invention was tested as follows:
[0357] Three 30 mg/mL samples of lyophilized
poly(L-lactide-co-ethyl-phosp- hate) microspheres were prepared,
the first having diameters greater than 75 microns, the second
having diameters within the range of 75-125 microns, and the third
having diameters within the range of 125-250 microns. Each sample
was injected intra-peritoneally into a group of 18 female CD-1 mice
having a starting body weight of 25 g. Animals in each group were
weighed, sacrificed, and necropsied at 2, 7 and 14 days, and at 1,
2 and 3 months. Any lesions detected during the necropsy were
graded on a scale of 0 to 4, with 0 indicating no response to
treatment and 4 indicating a severe response to treatment.
[0358] Inflammatory lesions were observed to be restricted to an
association with the microspheres on peritoneal surfaces or within
fat tissue, and were compatible with foreign body isolation and
encapsulation. Focal to multifocal supportive peritoneal steatitis
with mesothelial hyperplasia was observed at 2-7 days, but
gradually resolved by macrophage infiltration, the formation of
inflammatory giant cells, and fibrous encapsulation of the
microspheres at later sacrifices. Occasional adherence of
microspheres to the liver and diaphragm, with associated
inflammatory reaction, was also seen. Lesions related to
microspheres were not seen within abdominal or thoracic organs.
Microspheres, which were detected throughout the duration of the
study, appeared transparent at early sacrifices but, at later
times, developed crystalline material internally. No effects on
body growth were observed. The peritoneal reaction was observed to
be limited to areas directly adjacent to the microspheres with no
apparent deleterious effects on major thoracic or abdominal
organs.
[0359] Similar intraperitoneal injection of DAPG-EOP into male and
female S-D rats gave the following results:
16 Dose Level Initial No. Cumulative (mg/ Test in Test
Mortality.sup.a kg) Material M F M F 0 10% 25 25 0 0 Dextran 40 in
0.9% Saline 30 DAPG-EOP 25 25 1 0 100 DAPG-EOP 25 25 0 0 300
DAPG-EOP 25 25 0 0 .sup.aRepresents animals found dead or
sacrificed in moribund condition during study period. M = Male; F =
Female
Example 35
[0360] Synthesis of the Poly(phosphoester) P(trans-CHDM-HOP) 34
[0361] Under an argon stream, 10 g of trans-1,4-cyclohexane
dimethanol (CHDM), 1.794 g of 4-dimethylaminopyridine (DMAP), 15.25
ml (14.03 g) of N-methyl morpholine (NMM), and 50 ml of methylene
chloride, were transferred into a 250 ml flask equipped with a
funnel. The solution in the flask was cooled down to -15.degree. C.
with stirring, and a solution of 15.19 g of hexyl
phosphorodichloridate (HOP) in 30 ml of methylene chloride was
added through the funnel. The temperature of the reaction mixture
was raised to the boiling point gradually and maintained at reflux
temperature overnight.
[0362] The reaction mixture was filtered, and the filtrate was
evaporated to dryness. The residue was re-dissolved in 100 ml of
chloroform. This solution was washed with 0.1 M solution of a
mixture of HCl and NaCl, dried over anhydrous Na.sub.2SO.sub.4, and
quenched into 500 ml of ether. The resulting flowable precipitate
was collected and dried under vacuum to form a clear pale yellow
gelatinous polymer with the flow characteristics of a viscous
syrup. The yield for this polymer was 70-80%. The structure of
P(trans-CHDM-HOP) was ascertained by .sup.31P-NMR and .sup.1H-NMR
spectra, as shown in FIG. 27, and by FT-IR spectra. The molecular
weights (Mw=8584; Mn=3076) were determined by gel permeation
chromatography (GPC), as shown in FIG. 28, using polystyrene as a
calibration standard.
Example 36
[0363] Synthesis of the Poly(Phosphoester) P(cis &
trans-CHDM-HOP)
[0364] Poly(phosphoester) P(cis/trans-1,4-cyclohexane-dimethanol
hexyl phosphate) was prepared by following the procedure described
above in Example 34 except that a mixture of cis- and
trans-1,4-cyclohexane-dimeth- anol was used as the starting
material. As expected, the product cis-/trans-P(CHDM-HOP) was less
viscous than the trans isomer obtained in Example 34.
Example 37
[0365] Synthesis of Low Molecular Weight P(CHDM-HOP)
[0366] Under an argon stream, 10 g of trans-1,4-cyclohexane
dimethanol (CHDM), 15.25 mL (14.03 g) of N-methyl morpholine (NMM),
and 50 mL of methylene chloride were transferred into a 250 mL
flash equipped with a funnel. The solution in the flask was cooled
down to -40.degree. C. with stirring. A solution of 15.19 g of
hexyl phosphoro-dichloridate (HOP) in 20 mL of methylene chloride
was added through the funnel, and an additional 10 mL of methylene
chloride was used to flush through the funnel. The mixture was then
brought up to room temperature gradually and kept stirring for four
hours.
[0367] The reaction mixture was filtered, and the filtrate was
evaporated to dryness. The residue was re-dissolved in 100 ml of
chloroform. This solution was washed with 0.5 M mixture of HCl-NaCl
solution, washed with saturated NaCl solution, dried over anhydrous
Na.sub.2SO.sub.4, and quenched into a 1:5 ether-petroleum mixture.
The resulting oily precipitate was collected and dried under vacuum
to form a clear, pale yellow viscous material. The structure of the
product was confirmed by .sup.1H-NMR, .sup.31P-NMR and FT-IR
spectra.
Example 38
[0368] Synthesis of the Poly(phosphoester) P(trans-CHDM-BOP) 35
[0369] Under an argon stream, 10 g of trans-1,4-cyclohexane
dimethanol (CHDM), 0.424 g (5w) of 4-dimethylamino-pyridine (DMAP),
15.25 mL (14.03 g) of N-methyl morpholine (NMM) and 50 mL of
methylene chloride were transferred into a 250 mL flask equipped
with a funnel. The solution in the flask was cooled down to
-40.degree. C. with stirring. A solution of 13.24 g of butyl
phosphoro-dichloridate (BOP) in 20 mL of methylene chloride was
added through the funnel, with an additional 10 mL of methylene
chloride being used to flush through the funnel. The mixture was
heated to the boiling point gradually, and kept refluxing for four
hours. The reaction mixture was filtered, and the filtrate was
evaporated to dryness, taking care to keep the temperature below
60.degree. C. The residue was redissolved in 100 mL of chloroform.
The solution formed was washed with 0.5 M of HCl--NaCl solution and
saturated NaCl solution, dried over anhydrous Na.sub.2SO.sub.41 and
quenched into a 1:5 ether-petroleum mixture. The resulting oily
precipitate was collected and dried under vacuum to produce a
clear, pale yellow viscous material.
Example 39
[0370] Rheological Properties of P(trans-CHDM-HOP)
[0371] P(trans-CHDM-HOP) remained in a flowable gel-like state at
room temperature. The polymer exhibited a steady viscosity of 327
Pa.multidot.s at 25.degree. C. (shown in FIG. 29B), and a flowing
active energy of 67.5 KJ/mol (shown in FIG. 29A).
Example 40
[0372] In Vitro Cytotoxicity of P(trans-CHDM-HOP)
[0373] Cover slips were coated with P(trans-CHDM-HOP) by a spin
coating method. The coated coverslips were then dried and
sterilized by UV irradiation overnight under a hood. A
P(trans-CHDM-HOP)-coated cover slip was placed at the bottom of
each well of a 6-well plate. 5.times.10.sup.5 HEK293 (human
embryonic kidney) cells were plated into each well and cultured for
72 hours at 37.degree. C. The resulting cell morphology was
examined, using tissue culture polystyrene (TCPS) as a positive
control. The cells growing on the P(CHDM-HOP) surface proliferated
at a slightly slower rate, as shown by FIG. 30. However, the
morphology of cells grown on the polymer surface was similar to the
morphology of cells grown on the TCPS surface.
Example 41
[0374] In Vitro Degradation of P(CHDM-Alkyl Phosphates)
[0375] Each of the following poly(phosphate)s was prepared as
described above:
17 TABLE 11 Polymer Side Chain P (CHDM-HOP) -O-hexyl group P
(CHDM-BOP) -O-butyl group P (CHDM-EOP) -O-ethyl group
[0376] A sample of 50 mg of each polymer was incubated in 5 mL of
0.1 M, pH 7.4 phosphate buffer saline (PBS) at 37.degree. C. At
various points in time, the supernatant was poured out, and the
polymer samples were washed three times with distilled water. The
polymer samples were then extracted with chloroform, and the
chloroform solution was evaporated to dryness. The residue was
analyzed for weight loss by comparing with the original 50 mg
sample. FIG. 31 graphically represents the effect of the side chain
structure on the in vitro degradation rate of poly(phosphates) in
PBS.
Example 42
[0377] In Vitro Release Profile of Protein by P(CHDM-HOP)
[0378] The polymer P(CHDM-HOP) was blended with the protein
FITC-BSA (bovine serum albumin, a protein, tagged with the
fluorescent label FITC; "FITC-BSA") at a 2:1 (w/w) ratio (33%
loading). Measured amounts (66 mg or 104 mg) of the polymer-protein
blend were placed into 10 ml of PBS (0.1M, pH 7.4), a phosphate
buffer. At regular intervals (roughly every day), the samples were
centrifuged, the supernatant buffer was removed and subjected to
absorption spectroscopy (501 nm), and fresh amounts of buffer were
added to the samples. The resulting release curve, plotting the
cumulative percentage of FITC-BSA released versus time, is
graphically represented in FIG. 32. The loading level of the
protein in both cases was 33 weight %.
Example 43
[0379] In Vitro Protein Release Profile At Various Loading
Levels
[0380] FITC-BSA was blended with P) (CHDM-HOP) at different loading
levels (1%, 10% and 30%) at room temperature until the mixture
formed a homogenous paste. 60 mg of the protein-loaded polymer
paste was placed in 6 mL of 0.1 M phosphate buffer and constantly
shaken at 37.degree. C. At various time points, samples were
centrifuged, and the supernatant was replaced with fresh buffer.
The released FITC-BSA in the supernatant was measured by UV
spectrophotometry at 501 nm. FIG. 7 graphically represents the in
vitro release kinetics of FITC-BSA as a function of loading
level.
Example 44
[0381] Effect of Side Chain Structure on In Vitro Protein Release
Kinetics of FITC-BSA
[0382] The following three polymers were prepared as described
above: P(CHDM-EOP)
[0383] P(CHDM-BOP) and
[0384] P(CHDM-HOP)
[0385] FITC-BSA was blended with each polymer at a 10% loading
level at room temperature to form a homogenous paste. 60 mg of the
protein-loaded polymer paste was placed in 6 mL of 0.1 M phosphate
buffer with constant shaking at 37.degree. C. At various time
points, samples were centrifuged, and the supernatant was replaced
with fresh buffer. The released FITC-BSA in the supernatant was
measured by UV spectrophotometry at 501 nm. FIG. 34 graphically
represents the in vitro effect of side chain variations on the
protein release kinetics of FITC-BSA at 10% loading level.
Example 45
[0386] In Vitro Small Molecular Weight Drug Release from
P(CHDM-HOP)
[0387] A P(CHDM-HOP) paste containing doxorubicin, cisplatin, or
5-fluorouracil, was prepared by blending 100 mg of P(CHDM-HOP) with
1 mg of the desired drug at room temperature, respectively. An
aliquot of 60 mg of the drug-loaded paste was placed in 6 mL of 0.1
M phosphate buffer at 37.degree. C. with constant shaking, with
three samples being done for each drug being tested. At various
time points, the supernatant was replaced with fresh buffer
solution. The levels of doxorubicin and 5-fluorouracil in the
supernatant were quantified by UV spectrophotometry at 484 nm and
280 nm, respectively. The cisplatin level was measured with an
atomic absorbance spectrophotometer. FIG. 9A shows the release of
these low molecular weight drugs from P(CHDM-HOP).
[0388] FIG. 9B shows the release of hydrophobic small molecules,
such as paclitaxel, from p(CHDM-HOP).
Example 46
[0389] In Vitro Release Profile of Doxorubicin and Cisplatin from
P(CHDM-HOP)
[0390] A paste was made by blending 300 mg of P(CHDM-HOP) with 6 mg
of doxorubicin and 6 mg of cisplatin at room temperature to form a
uniform dispersion. A sample of 100 mg of the paste was incubated
in 10 mL of phosphate buffer (pH 7.4) at 37.degree. C. with
shaking. At different time points, samples were centrifuged, 9 mL
of the supernatant were withdrawn and replaced with fresh buffer.
The withdrawn supernatant was assayed spectrophotometrically at 484
nm to determine the amount of doxorubicin released into the
withdrawn supernatant, and the cisplatin release was measured by
atomic absorbance spectrophotometer. FIG. 36 graphically represents
the simultaneous release of cisplatin and doxorubicin from
P(CHDM-HOP).
Example 47
[0391] In Vivo Biocompatibility of P(trans-CHDM-HOP)
[0392] The polymer P(trans-CHDM-HOP) was synthesized as described
in Example 1. To facilitate injection, ethyl alcohol was added to
the polymer at levels of 10% and 20% by volume to reduce the
viscosity. Samples of 25 .mu.L of the polymer alone, 25 .mu.L of
the polymer containing 10% alcohol, and 25 .mu.L of the polymer
containing 20% alcohol, were injected into the back muscles of
Sprague Dawley rats. Tissues at the injection sites were harvested
at either three or thirteen days post-injection, processed for
paraffin histology, stained with hematoxylin, eosin dye and
analyzed. Medical-grade silicon oil was injected into the control
group rats.
[0393] Histological examination of the back muscle sections of the
rats injected with the polymer diluted with ethanol showed no acute
inflammatory response. The level of macrophage presence was
comparable to that of the control group, which had been injected
with medical-grade silicon oil, and neutrophils were not present in
any of the samples taken on either the third or thirteenth day.
Example 48
[0394] Controlled Delivery of Interleukin-2 and Doxorubicin from
P(CHDM-HOP) in an In Vivo Tumor Model
[0395] Lyophilized interleukin-2 ("IL-2") was purchased from
Chiron, mouse Interferon-.gamma. ("mIFN-.gamma.") was obtained from
Boehringer Mannheim, and doxorubicin hydrochloride ("DOX") was
obtained from Sigma. C57BL/6 mice, 6-8 weeks of age, were obtained
from Charles River. The aggressive melanoma cell line B16/F10 was
used to cause tumors in the mice, and the cells were maintained by
weekly passages. The polymer P(CHDM-HOP) was synthesized as
described in Example 35.
[0396] Mice were randomly allocated into groups as shown below in
Table 12. The day of tumor injection with cells of the melanoma
cell line was denoted as Day 0. Each mouse received a subcutaneous
injection of 50 .mu.l (10.sup.5) tumor cells in phosphate buffer
saline (PBS) in the left flank. On Day 3 or Day 7, the
tumor-bearing mice were selectively injected in the right flank
with one of the following formulations: (1) a bolus of IL-2, (2) a
bolus of DOX, (3) a polymer paste of IL-2, (4) a polymer paste of
DOX, (5) a polymer paste containing both IL-2 and DOX, or (6) a
polymer paste containing both IL-2 and mIFN-.gamma.). A control
group and negative control group received no further injections on
Day 3 or Day 7.
[0397] The bolus preparation of either IL-2 or DOX was prepared by
dissolving an appropriate amount of IL-2 or DOX in 50 .mu.l of
isotonic solution just prior to the injection. The polymer paste
formulations of either IL-2, DOX, a mixture of both IL-2 and DOX,
or a mixture of IL-2 and mIFN-.gamma., were prepared by blending 50
.mu.l of sterilized P(CHDM-HOP) with the drug(s) until
homogeneous.
18TABLE 12 Allocation of Groups of Mice for In Vivo Tumor Model
Number Day of of Injec- Group Mice tion Formulation Control 5 --
Nothing Negative 5 -- Nothing Control Bolus IL-2 8 3 0.8 .times.
10.sup.6 IU Bolus DOX 8 3 0.5 mg Bolus DOX 8 7 0.5 mg Paste IL-2 10
3 0.8 .times. 10.sup.6 IU Paste IL-2 10 7 0.8 .times. 10.sup.6 IU
Paste DOX 10 3 0.5 mg Paste DOX 10 7 0.5 mg Paste (IL- 10 3 0.8
.times. 10.sup.6 IU + 2 + DOX) 0.5 mg Paste (IL- 10 7 0.8 .times.
10.sup.6 IU + 2 + DOX) 0.5 mg Paste (IL- 10 3 10.sup.6 IU 2 + mIFN
.gamma.)
[0398] On Day 28 and Day 42 of tumor growth, the tumor sizes of the
various mice were measured. The results are shown below in Table
13, which shows the numerical data for the growth of tumor volumes
on Day 28 and Day 42 and the number of mice who survived the
experiment per drug grouping. Tumor volume was calculated as half
the product of the length and the square of the width, in
accordance with the procedure of Osieka et al., 1981.
19TABLE 13 CHDM-HOP Polymer as Carrier for Cytokine and Drug
Delivery in Melanoma Model Tumor Volume (mm.sup.3 .+-. SEM*) After
Initial Tumor Injection Number Number of Mice Survived Group of
Mice 28 days 42 days Control 5 No tumor No tumor Negative 5 2458
.+-. 1070.7 5656 Control 4 1 Bolus IL- 8 1946 .+-. 505.6 3282 .+-.
1403.3 2 (3d) 8 4 Bolus Dox 8 1218.9 .+-. 304.1 3942.5 .+-. 1818
(3d) 8 5 Bolus Box 8 1661.2 .+-. 301.8 4394.3 .+-. 741.3 (7d) 8 3
Paste IL- 10 934.1 .+-. 230 3183 .+-. 1223.4 2 (3d) 10 5 Paste IL-
10 2709.8 .+-. 397.3 10491 .+-. 2485.5 2 (7d) 10 3 Paste Box 10
1410 .+-. 475.3 4648.9 .+-. 1202.2 (3d) 8 7 Paste Dox 10 1480 .+-.
287 3915 .+-. 1739.7 (7d) 9 4 Paste 10 657.3 .+-. 248.9 3362.8 .+-.
1120.1 (IL-2 + 8 7 DOX) (3d) Paste 10 857.2 .+-. 243.6 3449.8 .+-.
1285.9 (IL-2 + 8 5 DOX) (7d) Paste 10 1217.9 .+-. 168.4 4469.8 .+-.
2018.7 (IL-2 + 9 4 mIFN-.gamma.) (3d) *Standard Error of the
Mean
[0399] Based on these measurements, the distribution of tumors
sizes were graphically represented in FIG. 37 for Day 28 (four
weeks after tumor implantation) and in FIG. 38 for Day 42 (six
weeks after tumor implantation). The graphs were subdivided into
plots according to the different treatments given to the
tumor-bearing mice.
[0400] The results on Day 28 showed that, in comparison with the
control group (tumor without treatment) and the bolus injection of
IL-2, the group of mice receiving a polymer/IL-2 paste injection
successfully delayed the tumor's growth. However, for the group of
mice not receiving a polymer/IL-2 paste injection until Day 7, the
tumor had already become of substantial size by Day 7 and,
accordingly, a significant reduction in tumor size was not
observed.
[0401] Excellent tumor reduction was obtained with the combination
of IL-2 and DOX. The average size of a tumor treated with an
injection of a polymer paste containing both IL-2 and DOX was
significantly smaller than the tumor in the control group.
Specifically, the average tumor size for mice receiving the IL-2
and DOX/polymer paste on Day 3 was 657.3 mm.sup.3, as opposed to
2458 mm.sup.3 for the control group. Even when treatment was
delayed until Day 7 of tumor growth, a therapeutic effect could
still be seen with the polymer paste formulation containing both
IL-2 and DOX.
[0402] The results on Day 42 of tumor growth also confirmed that
the Day 3 injection of polymer paste containing both IL-2 and DOX
gave the best result in delaying tumor growth. The combined therapy
of IL-2 and DOX in a polymer paste of the invention resulted in the
occurrence of smaller sized tumors in more of the test animals.
According to the distribution data shown in FIG. 15, there were
four mice bearing tumors of less than 1000 mm.sup.3 in the case of
the combined IL-2 and DOX polymer paste therapy, as compared with
only one mouse inside that range for the polymer paste injection of
DOX alone. It was also clear that IL-2 alone did not provide the
most desirable effect, as evaluated on the 42nd day of tumor
growth. Despite the good distribution of small tumor sizes on the
28th day, the long-time survival data appeared to be adversely
affected, not only by the progression of tumor growth at that
point, but also by the lack of continued, controlled delivery of
IL-2 over a longer time period. With the polymer paste formulation
of both IL-2 and DOX, the polymer degraded slowly, allowing a
gradual decrease in the diffusion rate of the therapeutic agent
over time.
[0403] However, because of the significant difference of the
distribution in tumor sizes inside each group the average tumor
size as seen in Table 13 did not provide a complete picture. A
fuller appreciation of the significance of the treatments of the
invention can be gained by comparing data from the distribution
graph of FIG. 38 which shows the dispersity in tumor sizes six
weeks after tumor implantation, with the survival curve shown in
FIG. 39, which shows the massive death of mice in all groups before
the Day 42 measurement, except for the groups of animals that had
received the 3rd day injection of paste containing either DOX alone
or the combination of IL-2 and DOX. Thus, the data, taken as a
whole, shows that the combined therapy of IL-2 and DOX in the paste
both significantly delayed tumor growth and extended life.
[0404] Early deaths about 3-4 days after the injections of the
DOX-containing polymer paste were thought to be due, at least in
part, to the toxic effect of DOX causing the deaths of the weaker
animals. Corresponding injections of bolus DOX did not produce
early death, probably because of the rapid distribution and
clearance from the body of the bolus-injected DOX.
Example 49
[0405] Incorporating Paclitaxel into P(CHDM-HOP) or P(CHDM-EOP)
[0406] 100 mg of each of the polymers p(CHDM-HOP) and p(CHDM-EOP)
was dissolved in ethanol at a concentration of about 50%. After the
polymer was completely dissolved, 5 mg of paclitaxel powder (a
chemotherapeutic drug) was added to the solution and stirred until
the powder was completely dissolved. This solution was then poured
into ice water to precipitate the polymer composition. The
resulting suspension was centrifuged, decanted, and lyophilized
overnight, to obtain a viscous gelatinous product.
Example 50
[0407] In Vitro Release of Paclitaxel from P(CHDM-HOP) and
P(CHDM-EOP)
[0408] In a 1.7 mL plastic micro centrifuge tube, 5 mg of both of
the paclitaxel polymer formulations of Example 20 to be tested was
incubated with 1 mL of a buffer mixture of 80% PBS and 20% PEG 400
at 37.degree. C. Four samples of each formulation to be tested were
prepared. At specific time points, approximately every day, the
PBS:PEG buffer was poured off for paclitaxel analysis by HPLC, and
fresh buffer was added to the microcentrifuge tube. The release
study was terminated at day 26, at which point the remaining
paclitaxel in the polymer was extracted with a solvent to do a mass
balance on paclitaxel.
[0409] The resulting release curves for the release of paclitaxel
from both polymers are shown in FIG. 18. The total paclitaxel
recovery was 65% for the P(CHDM-HOP) formulation and 75% for the
P(CHDM-EOP) formulation.
Example 51
[0410] In Vitro Release of Paclitaxel from P(DAPG-EOP)
[0411] P(DAPG-EOP) microspheres were prepared by a solvent
evaporation method, using ethyl acetate as the solvent and 0.5% PVA
in water as a non-solvent. The resulting microspheres are spherical
in shape with particle sizes ranging from about 20-150 .mu.m, most
preferably 20-50 .mu.m.
[0412] The in vitro release of paclitaxel from the microspheres was
carried out in PBS (pH 7.4) at 37.degree. C. To maintain a sink
condition, an octanol layer was placed on top of the PBS to
continuously extract the released paclitaxel. The released
paclitaxel was quantified using an HPLC method, and the in vitro
mass loss of the polymer was obtained by a gravimetric method. The
in vitro release of paclitaxel from the microspheres was slow and
continuous with concomitant polymer mass loss, as shown in FIG.
41.
Example 52
[0413] In Vivo Release of Paclitaxel from P(DAPG-EOP)
[0414] P(DAPG-EOP) microspheres were prepared as described above in
Example 52, and the In vivo release of paclitaxel from the
microspheres was studied on nude mice. Plasma was collected from
each of the test animals at 1, 14 and 28 days after injection, and
paclitaxel concentration was analyzed by HPLC with MS-MS detection.
For efficacy studies, test animals received intraperitoneal
injections of a human ovarian cancer cell line OVCAR3 obtained from
carrier animals. P(DAPG-EOP) microspheres incorporating paclitaxel
or paclitaxel without the biodegradable polymer were also given
intraperitoneally at one day post cell injection. The survival of
the animals was also monitored.
[0415] Following a single intraperitoneal administration of the
microspheres, a sustained level of paclitaxel in plasma was
obtained for at least 28 days, as shown below in Table 14:
20TABLE 14 Paclitaxel Plasma Concentration Paclitaxel Concentration
(ng/ml) Paclitaxel in Paclitaxel w/o Microspheres polymer (120 (125
mg/kg) mg/kg) 1 day 38.98 .+-. 7.53 357.67 .+-. 136.39 14 days 4.50
.+-. 1.21 Animal died 28 days 3.98 .+-. 0.99 Animal died
[0416] When a comparable dose of paclitaxel was given
intraperitoneally, the nude mice could not tolerate the dose due to
the toxicity.
[0417] The biodegradable polymer microsphere delivery system was
surprisingly effective in treating ovarian cancer in the animal
model OVCAR3. As shown in FIG. 42, superior efficacy was obtained,
as compared with paclitaxel without the biodegradable polymer.
Example 53
[0418] Median Survival Data for P(DAPG-EOP) Paclitaxel
[0419] P(DAPG-EOP) microspheres containing 10 mg/kg or 40 mg/kg
paclitaxel were injected into the peritoneums of test animals
having ovarian cancer. Other test animals were injected with
paclitaxel in an organic solvent, commercially available under the
trade name Taxol, at the same dosage levels. The test animals were
monitored, and median survival times were noted. The results are
summarized below:
21 Material Administered Median Survival Control 23 days Taxol, 10
mg/kg 64 days Taxol, 40 mg/kg 67 days Paclitaxel in 69 days
microspheres, 10 mg/kg Paclitaxel in 115 days microspheres, 40
mg/kg
[0420] These results are represented graphically in FIG. 43 and
indicate an unexpectedly large increase in median survival for the
test animals given the paclitaxel in the form of biodegradable
microspheres.
[0421] A comparison of a different set of dosage levels gave the
following similar data:
22 Material Administered Median Survival Control 30 days Taxol, 40
mg/kg 77 days Paclitaxel in 83 days microspheres, 4 mg/kg
Paclitaxel in 95 days microspheres, 10 mg/kg Paclitaxel in >110
days microspheres, 40 mg/kg
[0422] These results are represented graphically in FIG. 44 and
confirm the unexpectedly large increase in median survival for the
test animals given the paclitaxel in the form of biodegradable
microspheres. Additional graphical representations of this data are
provided by FIGS. 45 and 46.
[0423] The invention being thus described, it will be obvious that
the same may be varied in many ways. Such variations are not to be
regarded as a departure from the spirit and scope of the invention,
and all such modifications are intended to be included within the
scope of the following claims.
* * * * *